Synthesis, X-ray structure and reactions of (2-oxoalkyl)triarylbismuthonium salts

摘要

J. CHEM.SOC.PERKIN TRANS. 1 1994 Synthesis, X-ray Structure and Reactions of (2-0xoalkyl)triarylbismuthonium Yoshihiro Matano/ Nagao Azuma" and Hitomi Suzuki a Department of Chemistry, Faculty of Science, Kyoto University, Kitashiraka wa, Sakyo-ku, Kyoto 606-01,JapanDepartment of Chemistry, Faculty of General Education, Ehime University, Bunkyo -cho, Matsuyama 790, Japan Treatment of triarylbismuth difluorides 1 with silyl enol ethers 2 in the presence of boron trifluoride- diethyl ether or trimethylsilyl trifluoromethanesulfonate (triflate) gave (2-oxoalkyl)triarylbismuth-onium tetrafluoroborates.3 and triflates 4 in good yields. A similar reaction of the difluorides 1 with hexamethyldisiloxane in the presence of the latter acid reagent led to the formation of oxybis-(triarylbismuth) ditriflates 5.X-Ray cyrstallographic analyses of compounds 3a. 4a and 5a showed that the first two onium salts have a distorted tetrahedral geometry and the last, a p-0x0 type compound, has a distorted trigonal bipyramidal geometry around the bismuth centre. The stability of these bismuthonium salts may reasonably be attributed to the intramolecular coordinative interaction between the bismuth and oxygen atoms and also low nucleophilicity of the counter ions employed. The bismuthonium salt 3f readily underwent onium exchange with the phosphine 6 and the sulfide 9 to afford the corresponding phosphonium and sulfonium salts 7 and 10. The salts 3 and 4 also underwent coupling with a variety of nucleophiles such as the enolate 11, piperidine 13, the phenoxides 15, the thiolates 17,the sulfinate 19 and the halides 21 to afford the corresponding a-substituted ketones 12,14, 16,18,20 and 22 in moderate to good yields, together with a good recovery of triphenylbismuthine 8.Of all the onium-type compounds derived from 15th and 16th elements, bismuthonium is the least well known. Except for sporadic reports,'-6 the literature to date contains little information on the properties, structures and reactivities of bismuthonium salts probably because of the difficulty of access to this class of compounds. The first successful isolation of alkylbismuthonium compounds was reported by Goel and Prasad in 1971, who had carried out the metathetical reaction of triphenylbismuth dichloride with silver(1) salts in dry acetone to obtain acetonyltriphenylbismuthoniwn salts as a stable solid.6 However, when a similar reaction was carried out in acetylacetone or ethyl methyl ketone, tetraphenyl- bismuthonium salts were the sole bismuth-containing products isolated.'Although the formation of alkylbismuthoniwn com- pounds has also been reported in the reactions of triphenyl- bismuthine with hexachloro-s-trithiane 1,1,3,3,5,5,-hexaoxide,* norbornadien-7-yl tetrafluoroborate and a carbonyl-stabilized sulfonium ylide in the presence of sodium tetraphenylborate, the products described therein were not well characterized.Although the above approaches are of interest from the mechanistic point of view, they lack generality as a preparative method for alkylbismuthonium salts since the alkyl ligands to be introduced are limited to specific cases.In a recent communication,' we have reported an efficient synthesis and X-ray structure analysis of a stable (2-oxoalky1)triarylbis- muthonium tetrafluoroborate. In this article, we describe full details of the synthesis, properties, structures and reactions of such alkylbismuthonium salts and related compounds. Results and Discussion Synthesis of Stable (2-0xoalkyl)triarylbismuthoniumSalts.-In order to obtain alkylbismuthonium salts stable enough to be handled at room temperature, two key points must be taken into consideration. First is the combination of starting reagents. In contrast to the ease of access to the corresponding phosphonium and arsonium compounds, bismuthonium salts are not accessible by the direct interaction of triarylbismuthines with halogenoalkanes because of the low nucleophilicity of tertiary bismuthines whose unshared electron pair is of a strong s character.7 This implies that an alternative combination of an electrophilic hypervalent bismuth compound and a nucleo- philic alkyl-transfer reagent would be a more appropriate choice for preparing such onium-type compounds.Second is the choice of counter anions for bismuthonium salts. Tetra- phenylbismuthonium chloride decomposes within a few min- utes at room temperature to yield triphenylbismuthine and chlorobenzene through reductive elimination in accord with the high nucleophilicity of the chloride ion.2 This instability of bismuthonium chlorides suggested to us the need to use less nucleophilic counter anions such as tetrafluoroborate and trifluoromethanesulfonate (triflate) for the successful isolation of the desired products.Based on these considerations, we chose a combination of triarylbismuth difluoride 1,silyl enol ether 2 and boron trifluoride-diethyl ether (BF,*OEt2)/ trimethylsilyl triflate (Me,SiOTf) as starting materials. As expected, the reaction of the difluorides 1 with BF,-OEt, in dichloromethane, followed by treatment with the enolates 2 gave (2-oxoalkyl)triarylbismuthoniumtetrafluoroborates 3 in high yields (Scheme I). In this reaction, the Lewis acid BF3*OEt2 plays a dual important role, in that, initially it activates compound 1 and then in the second stage stabilizes the bismuthonium salt 3 as the counter anion BF4-.In the absence of BF3=OEt2, the starting materials 1 and 2 were recovered unchanged. This synthetic methodology proved to be quite efficient and generally applicable to the construction of homologous bismuthonium salts. When Me,SiOTf was substi- tuted for BF3*OEt2, the corresponding bismuthonium triflates 4 were obtained (Scheme 1). In order to gain insight into the reaction pathway, the process leading to the formation of the onium salt 3a was monitored by 'H and 13CNMR spectroscopy; mixing of the difluoride la and ~ 7 For example, a mixture of triphenylbismuthine and phenacyl bromide were recovered unchanged after 48 h refluxing in benzene while triphenylphosphine and phenacyl bromide produced phenacyltriphenyl- phosphonium bromide in a quantitative yield within 5 min in dichloromethane at room temperature.Rk= a R=Bu' L J b R=Bu' 3 c R=Bd a Ar= Ph, R = Buf d R=Pr' b Ar=Ph, R=B# o R=Me' c Ar=Ph, R=B~ R=Ph g R = p-BrCamp;l, d Ar=Ph, eAr=Ph, R=Pr' R=Me f Ar=Ph, R=Ph g Ar = Ph, R = p-BCeH4 h Ar = p-Tol, R = Bd Ar3BiF2- I J Ar= P-ToI, R = Bu8 Ar=p-Tol,R=Bu' 1 k Ar=p-Tol,R=Ph a Ar=Ph b Ar = p-To1 4 a R=Ph, R=Bu' b Ar = Ph, R = Bu8 c Ar=p-Td, R=Bu' d Ar = p-Tol, R = Bus Me3SiOSie3 Ar3Bi0 Bik3 II roomtemp. TfO OTf 5 a Ar=Ph b Ar = p-To1 Scheme 1 BF3*OEt2 in CDCl, at 0 "C gave a colourless solution, where the original sets of 'H and 13CNMR signals for the phenyl rings in the difluoride la changed into a new set of signals arising from a presumed association complex.* When the silyl enolate 2a was added to this solution, its spectral pattern immediately changed to that for the superimposed spectra of compound 3a and fluorotrimethylsilane (Me3SiF).I2 It is likely that the coordination of BF, to difluoride la yields fluorotriphenyl- bismuthonium tetrafluoroborate BiFPh, BF, as an initial product, which suffers nucleophilic attack by the silyl enolate 2a on the bismuth centre with simultaneous elimination of Me,SiF, ultimately leading to bismuthonium salt 3a as the final product. The high affinity of both boron and silicon atoms for fluorine is, no doubt, the key factor in driving the reaction.The alkylbismuthonium salts 3 and 4 were purified by recrystallization or by column chromatography on silica gel and characterized on the basis of microanalysis and NMR, IR and FAB mass spectroscopy. All the crystalline alkylbis- muthonium salts obtained showed sharp melting points and when the melt was rapidly cooled to ambient temperature, they were recovered unchanged. Prolonged heating of the melt at temperatures above the melting point, however, led to gradual decomposition to give a complex mixture of products. For example, compound 3a (m.p. 143-145 "C)heated at 155-160 "C * NMR (200 MHz; CDCl,); lad, 7.49 (3 H, t, J7.6), 7.66 (6 H, t, J7.7) and 8.22(6H,d,J7.8);Sc 131.7,131.9,134.3and 153.6;Ph3FBi+BF4- dH7.62(3H,t,J7.8),7.81 (6H,t,J7.9)and8.07(6H,d,J7.9);Sc133.0, 133.3, 134.0 and 154.1; Me,SiFd, 0.22 (9 H, d, JHF 7.3) lit.," dH0.19 (9 H, d, JHF 7.23).J. CHEM. SOC. PERKIN TRANS. 1 1994 for 30 min gave a dark purple mixture of degradation products composed of benzene, pinacolone and insoluble pale grey substances. This type of compound exhibits highly characteristic spectral features; 'H NMR spectra show a signal in the range BH 5.22-5.97 for the methylene group bound to the cationic bismuth atom. I3C NMR signals due to the methylene and phenyl carbons adjacent to the bismuth atom are observed at 6, 54.8- 58.6 and 135.5-142.6, respectively. The appearance of these signals at lower field is in accord with the electron-withdrawing effect of the bismuthonium moiety.FAB mass spectra display a strong peak due to M+-BF4 fragment for the tetrafluoroborate 3 and M+-OTf one for the triilate in accord with the cationic nature of the quaternary bismuth centre. The additional diagnostic feature is strong IR absorption characteristic of their counter anions. Broad intense bands appear around 1150-950 cm-' (BF,-) for 3 and 1320-1 120 cm-' (OTf-) for 4. Carbonyl stretching frequencies were observed as sharp absorption at 1674-1 696 cm-'. These spectral features clearly indicate the onium nature of compounds 3 and 4, accompanied by spatially separated counter anion. The salts 3 and 4 are soluble in dichloromethane, chloroform and acetonitrile, but very poorly soluble in benzene, hexane, ether and tetrahydrofuran (THF).All isolated bismuthonium salts are stable and can be handled without change exposed to the air.? In view of the instability of quaternary bismuth halides under ambient conditions,2 the low nucleophilic nature of the counter anions BF,- and OTf- should be essential for the thermal stabilization of compounds 3 and 4. The twin advantages of our method for the preparation of alkylbismuthonium salts 3 and 4 over previous ones 5*6*8-10 is that it uses easily available reagents with simpler manipul- ation. As an extension, this methodology was applied to the synthesis of some pox0 type bismuth compounds. Treatment of the triarylbismuth difluorides 1 with hexamethyldisiloxane in the presence of Me,SiOTf afforded oxybis(triary1bismuth) ditriflates5 in good yields (Scheme 1).I3C NMR spectra of this type of compounds show a characteristic peak for the ips0 carbons of the aromatic rings at 6,150.1 and 150.9. The lowfield resonance is suggestive of the hypervalent nature of the bismuth centre in compound 5. IR absorption due to the asymmetric stretching of the Bi-O-Bi bond appears at 634 and 637 cm-', which is in accord with the reported values for the analogous system (Ph,BiOBiPh,)X2 .I3 X-Ray Structure Analysis.-To date, X-ray structural data for bismuthonium salts has been reported for only three compounds: BiPh,C104, l4BiPh,OTs ' and BiPh,- Ph2Bi(OCOCF,)2.1S However, until now there has been no information for analogous alkyl substituted compounds. We disclose here the X-ray diffraction analysis results for two such alkylbismuthonium salts, namely compounds 3a and 4a (Table 1).$As shown in Figs. 1 and 2, the bismuth atom in each salt has a distorted tetrahedral geometry with the respective bond angles C-Bi-C 102.1(7)-118.4(7)" for 3a and 102.6(6k117.4(6)0 for 4a, which clearly endorse the onium nature of the central bismuth atom (Tables 2 and 3).The mean Bi-C bond lengths 2.20(2) 8, for 3a and 2.19(2) 8, t Compounds 3 and 4 are not sensitive to atmospheric moisture, but prolonged contact of the latter with water led to gradual hydrolysis to form p-0x0 type of compound 5. $The X-ray structure of 3a has been reported briefly in our recent letter," and its PLUTO drawing and bond parameters are reproduced herein for comparison.The crystal structure of 4a consists of two isolated molecules which differ little from each other as to the configuration of central bismuth atom. The PLUTO structure shown in Fig. 3 and bond parameters listed in Table 4 are those of the selected molecule. J. CHEM. soc. PERKIN TRANS. 1 1994 1741 Table 1 Crystal data for compounds 3a, 4a and 5a Compound 3a 4a 5a Dimensions/mm 0.180 x 0.180 x 0.300 0.180 x 0.150 x 0.200 0.130 x 0.130 x 0.480 Formula C,,Hz6BBiF4O C2,H,,BiF30,S C38H30Bi2F607S2 Formula weight 626.25 688.51 1194.72 Crystal colour, Habit Colourless, prism Colourless, prism Colourless, prism Crystal structure Rhombohedra1 Triclinic Monoclinic (hexagonal axes) Space group RW) PT n,/aalA 30.606(7) 13.307(7) 19.730(4) blA 1 9.974( 3) 10.3 14(2) CIA 14.195(5) 10.480(3) 21.143(3) El" 100.44(2) 100.06(4) 109.26( 1) Pl" Yl" 82.03(3) VIA3 11 514(6) 2681(3) 4062(1) Z 18 2 4 DJg cmV3 1.625 1.706 1.954 Fooo 5436 1336 2264 p/cm-' 69.09 66.78 87.98 Radiation @/A) MoKu, 0.710 69 MoKu, 0.710 69 MoKu, 0.710 69 Temp.(T/OC) 27 27 25 28(max)p 55.0 55.0 50.0 Scan rate (deg min-') 8.0 16.0 16.0 Scan width (deg) C0.79 + 0.30 tan C0.94 + 0.30 tan 8 cl.05 + 0.30 tan 8 Total data 6052 10 454 8537 Unique data 5684 9927 7557 R(int) 0.091 0.052 0.051 No. observed 1899 3997 3348 I 3.000(I) I 3.000(1) I 3.000(1) No.variables 280 61 3 497 R 0.049 0.045 0.039 Rw 0.045 0.045 0.034 w Fig. 1 A PLUTO drawing of compound 3a with the atomic Fig. 2 A PLUTO drawing of compound 4a with the atomic numbering scheme numbering scheme. The triflate anion is omitted for clarity. for 4a are comparable with those of reported tetraaryl- is appreciably reduced. Another noteworthy feature is the bismuthonium compound^.'^^^^ The bond angle open to the distance between the bismuth and carbonyl oxygen atoms carbonyl oxygen side C( 13)-Bi( l)-C( 19) 1 18.4(7)" for 3a and 2.90(1) 8,for 3a and 2.93(1) 8, for 4a, which is longer than the C(37)-Bi(2tC(49) 117.4(6)" for 4a is considerably larger than sum of the covalent radii (2.10 8,) but shorter than that of the the expected value for an sp3 configuration (109O28'), while the estimated van der Waals radii (3.72 These findings C-Bi-C angle remote from the carbonyl function C( 1 )-Bi( 1)-strongly suggest the existence of an intramolecular interaction C(7) 102.1(7)O for 3a and C(31)-Bi(2)-C(43) 105.4(6)' for 4a between the carbonyl oxygen and electron-deficient bismuth Table 2 Selected bond lengths (A) and angles (") for compound 3a, with estimated standard deviations in parentheses Bond length Bond angle Bi( 1)-C( 1) 2.20(2) C( l)-Bi(ljC(7) 102.1 (7) Bi(1 jC(7) 2.21(2) C(1)-Bi(1 jC(13) 107.0(7)Bi( l)-C( 13) 2.19(2) C( 1)-Bi(1 jC( 19) 110.6(6)Bi(l)-C(19) 2.20(2) C(7)-Bi(ljC(13) 105.6(8)C(19jC(20) 1.49(2) C(7)-Bi(l)-C( 19) 1 1 1.8(7) C(20)-0( 1) 1.22(2) C( 13)-Bi( 1)-C( 19) 118.4(7)Bi( 1) O(1) 2.90( 1) C( 19jC(20)-0( 1) 1 19(2) Bi( 1 )-C( 19)-C(20) 106( 1) Table 3 Selected bond lengths (A) and angles (") for compound 4a, with estimated standard deviations in parentheses Bond length Bond angle ~~~~~ ~ Bi(2 jC(3 1) 2.17(2) C(3 l)-Bi(2)-C(37) 102.6( 6) Bi(2)-C(37) 2.24(2) C(31)-Bi(2)-C(43) 105.4(6) Bi(2jC(43) 2.17(2) C(31)-Bi(2 jC(49) 112.2(6) Bi(2 jC(49) 2.17(2) C(37)-Bi(2 jC(43) 105.5(6) C(49 jC(50) 1.45(2) C(37)-Bi(2)-C(49) 1 17.4(6) C(50k0(2) 1.22(2) C(43)-Bi(2)-C(49) 112.5(6) Bi(2) O(2) 2.93(1) C(49)-C(50)-0(2) 119(2) Bi(2)-euro;(49)-euro;( 50) 109( 1) w Fig. 3 A PLUTO drawing of compound 5a with the atomic numbering scheme.The triflate groups are omitted except for O(2) and O(5) atoms for clarity.atoms. In both salts, the tetrafluoroborate and triflate anionic portions are spatially separated and seem to have only weak electrostatic interaction with the bismuth centre.* In order to determine what electronic influence the hetero atom attached to the bismuth has, an X-ray analysis of compound 5a has also been carried out (Fig. 3 and Table 4). In this molecule, the geometry around each of the two bismuth centres linked by the oxygen bridge is somewhat distorted trigonal bipyramidal with * Although a possible interaction between the bismuth and the nearest sulfonyl oxygen atom in 4a cannot be completely excluded, the observed distance 3.16(1) A is too long as compared with that (2.77 A) of the distorted trigonal bipyramidal compound Ph,-Bi + OTs -.J. CHEM. SOC. PERKIN TRANS. 1 1994 Table 4 Selected bond lengths (A) and angles (") for compound 5a, with estimated standard deviations in parentheses Bond length Bond angle Bi( 1 W(3) Bi( l)-C(9) Bi(ltC(l5) Bi(2)-C(21) Bi(2)-C(27) Bi(2)-C(33) Bi(ljO(1) Bi( 1)-0(2) Bi(2jO( 1) Bi(2)-0(5) 2.20( 1) 2.20(2) 2.22(1) 2.19(1) 2.20(1) 2.21(1) 2.039(8) 2.58(1) 2.091(8) 2.527(9) C(3tBi(l-C(9)C( 3)-Bi( 1 )-C( 1 5) C(9tBi( 1 )-C( 1 5) C(21)-Bi(2)-C(27) C(21 jBi(2)-C(33) C(27)-Bi( 2)-C( 33) O(1tBi( 1 )-omO(ltBi(ljC(3)0(1 jBi(1 jC(9) O(1 )-Bi( lkC( 15) O(ltBi(2)-0(5) O(1 )-Bi(2)-C(2 1) O(l)-Bi(2)-C(27) O(ljBi(2)-C(33) Bi( 1 jO(1 )-Bi(2) 119.3(7) 112.7(6) 124.4( 5) 11 3.9(6) 130.5(5) 113.3(5) 176.4(3) 98.9(5) 97.7( 5) 92.4(5) 179.7( 3) 93.2( 5) 100.4(4) 92.6(4) 134.0(4) three phenyl groups at equatorial sites.As expected, the electronegative oxygen atoms occupy axial positions with the bond angles O(1)-Bi( 1)-0(2) 176.4(3)O and O(1)-Bi(2)-0(5) 179.7(3)". The mean Bi-C(Ph) distance 2.20(1) 8, and the mean C(Ph)-Bi-C(Ph) angle (119.0") are not significantly different from those 2.19(2) 8, and 118.5" reported for (Ph3BiOBiPh,)(C104)2.1 The bismuth atoms are located above the plane formed by three @so phenyl carbon atoms by 0.24 8, for Bi(l) and 0.20 8, for Bi(2) slightly bent towards the bridging oxygen atom with a mean O(bridgekBi-C(Ph) angle 95.9". The Bi-O(bridge) distances 2.039(8) and 2.091(8) 8, agree with the values expected for the covalent Bi-O single bond, while the Bi-O(triflate) distances 2.58( 1) and 2.527(9) 8, are too long to be covalent.These findings may be taken to suggest some contribution from the tetrahedral configuration to the bismuth centre in compound 5 and an intermediate character of the Bi-O(triflate) bonding between the formal covalent and ionic ones. Thus, the bismuth atom in compound 4a is of onium nature while those in 5a are of hypervalent nature, as reflected by the tetrahedral configuration of 4a and trigonal bipyramidal of 5a, respectively. The origin of different geometry between com- pounds 4a and 5a may be attributed to the difference in ability for electron-withdrawal of the alkyl carbon atom in 4a and the bridging oxygen atom in 5a.Reactions of Alkylbismuthonium Salts 3 and 4 with some Nucleophi1es.-Although synthetic chemistry based on organo- bismuth(v) compounds was extensively developed by Barton's group in the 1980's,'*'* the possible use of bismuthonium salts in such a way has not been explored. In order to estimate the synthetic potential of alkylbismuthonium salts, the reactions of compounds 3 and 4 with several nucleophiles have been examined (Schemes 2 and 3 and Table 5). When treated with the triphenylphosphine 6 or the dimethyl sulfide 9, compound 3f readily underwent onium exchange to give phenacyltriphenylphosphonium tetrafluoroborate 7 and dimethylphenacylsulfonium tetrafluoroborate 10,respectively. Triphenylbismuthine 8 was recovered quantitatively in accord with the high nucleophilic character of light pnictogen and chalcogen elements (Scheme 2).Treatment of compound 3 with the sodium enolate 11 generated from dibenzoylmethane in THF at room temperature gave the corresponding tricarbonyl derivatives 12 and bis- muthine 8. Compound 3f reacted with piperidine 13 to afford a-piperidinoacetophenone 14 in almost quantitative yield. Reaction of compounds 3 and 4 with sodium aryl oxides 15 in THF led to coupling between the alkyl carbon and oxygen atoms to give the a-aryloxy ketones 16 in moderate yields. With J. CHEM. SOC. PERKJN TRANS. I 1994 ro 1 3f 1L 7 10 Scheme 2 the sodium thiolate 17, the salts 3 and 4 underwent a similar type of C(alky1)-S coupling in THF, even at -20 "C, to afford a-arylthio ketones 18 in good yields, while the reaction with sodium toluene-p-sulfinate 19 led to a-sulfonyl ketones 20 in high yields.When treated with an excess of potassium bromide or iodide 21 in DMF at room temperature, the salt 3underwent C(alky1)-halogen coupling to give the corresponding a-halo- geno ketones 22 together with bismuthine 8. Characteristic colouration was observed at the initial stage of the reaction with some nucleophiles. A clear yellow solution formed immediately after a nucleophile was mixed with compound 3 or 4 in THF at -50 "C; this colour was dis- charged, when the mixture was allowed to warm to room temperature (in the cases of 11and 15) or heated under gentle reflux (in the case of 17). The resulting colourless solution was found to contain a-substituted ketones 12, 16 or 18, and triphenylbismuthine8.TLC monitoring of the reaction mixture showed that the discolouration is a sign that the coupling reaction is complete.Judging from these findings, it is reasonable to assume that an intermediary organobismuth(v) species generated from the salt 3 or 4 and a nucleophile is responsible for the yellow colouration, although there is as yet no direct evidence for the intermediacy of such a species. In the reaction of compound 3a or 4a with p-tolylmagnesium bromide, phenyllithium or butyllithium at -78 "C, a charac- teristic colour initially developed (purple for the Grignard * and orange for the lithium reagents), which gradually turned colourless or pale yellow as the temperature was raised to ambient.In every case the products were triphenylbismuthine 8 and a complicated mixture of unidentified compounds. It is interesting that the 2-oxoalkyl moiety, which is intrinsic- ally preferred as an enolate anionic species, can be transferred as an acylmethyl cation equivalent from salt 3 or 4 to a nucleophile in these reactions, where the loss of triphenyl- bismuthine 8 as a neutral species from energy-rich bismuth- onium salt should be a key factor for promoting the C-Nu bond formation whether an intermediary pentavalent species may be involved or not. The reactions described here are the first example of alkyl transfer from alkylbismuthonium salts, and its synthetic potential will be subject to our further study.Experimenta1 General.-All reactions were carried out under an atmos- phere of argon. Dichloromethane (CH,Cl,) and tetrahydro- * Pentaphenylbismuth has a deep-purple colour and decomposes in chloroform to give triphenylbismuthine, benzene, and tarry products presumably derived from an intermediary benzyne. l9 In the present case a similar type of quinquenary bismuth compound might be generated at the low temperatures. 1743 Na+ 00 11 HF,-W-tRT Ph 00 12 14 ArONa+ 15 LOAr + 8 'HF, -50 "c -.) refl; R 16 0 ArS-Na' 17 -LSAr + 83 X=BF4 'HF,-50"CdRT R 4 X=OTf 18 p -TolSO,Na 19 -R LSOpTol-p+ 8 DMF. RT 20 KHal 21 *R kHal + 8 DMF, RT 22 RT = room temp.Scheme3 furan (THF) were distilled under argon from CaH, and sodium benzophenone ketyl, respectively, before use. N,N-Dimethyl- formamide (DMF) was distilled from CaH, and stored over molecular sieves 4 A. Triarylbismuth difluorides 1 were prepared from the corresponding dichlorides according to the reported method 2o and recrystallized from hexane-CH,Cl,. Silyl enol ethers 2 were prepared by a standard procedure.2' Other reagents were used as commercially received. Column chromatography was performed on silica gel (Wakogel, 200 mesh). All m.p.s were determined on a Yanagimoto hot-stage apparatus and are uncorrected. 'H and NMR spectra were recorded on a Varian Gemini-200 (200 MHz) spectrometer in CDCl, unless otherwise stated with tetramethylsilane as an internal standard.Coupling constants J are given in Hz.IR spectra were recorded on a Shimadzu FTIR-8100 spectro- photometer. EI mas spectra were obtained on a Shimadzu GCMS-QP2000A spectrometer and FAB mass spectra on a JEOL JMS-HS1 10 spectrometer using 3-nitrobenzyl alcohol as a matrix. Elemental analyses were performed at the Micro- analytical Laboratories of Kyoto University. Triurylbismuth dguorides. la, m.p. 159-161 "C (lit.," 158.5-159 "C);6, 7.49 (3 H, t, J7.6), 7.66 (6 H, d, J7.7) and 8.22 (6 H, d,J7.8).lb,m.p. 123-125"C;6,2.39(9H,s),7.45(6H,d,J8.2) and 8.07 (6 H, d, J 8.2). Silyl enol ethers. 2a, b.p. 48-50 "C/18 mmHg (lit.,,' 68 "C/80 mmHg);6,0.20(9H,s),1.04(9H,s),3.92(1H,d,J1.6)and4.08 (1H,d,J1.6).2b,b.p.56-58"C/18mmHg;6,0.20(9H,~),0.85 (3 H, t, J7.4), 0.99 (3 H, d, J6.9), 1.18-1.55 (2 H, m), 1.95 (1 H, sext, J6.9), 3.98 (1 H, s) and 4.00 (1 H, s).2c, b.p. 56-58 "C/18 mmHg;6,0.20(9H,s),0.89(6H,d, J6.5), 1.82-1.90(3H,m), 4.01 (1 H, s) and 4.04 (1 H, s). 26, b.p. 74-76 "C/135 mmHg; 6, 1744 J. CHEM. SOC. PERKIN TRANS. 1 1994 Table 5 Reactions of compounds 3 and 4 with some selected nucleophiles Entry Compd. R Nucleophile Product Yield ()" 1 3d Pr' 11 12a 69 2 3f Ph 11 12b 61 3 3f Ph 13 14 95 4 5 6 7 3a 3a 3a 4a Bur Bu' But BU' 15a(Ar = Ph)15b (Ar = 1-Naphthyl) 15b 15~(Ar = 4-CICamp;) 16a 16b 16b 16C 56 61 46 55 8 9 10 3a 3a 4a Bur BU' Bu' 17a(Ar = Ph) 17b(Ar = 4-CIC6H4) 17a 18a 18b 18a 77 72 65 11 4a Bur 17b 18b 73 12 3a Bu' 19 20s 87 13 3f Ph 19 20b 82 14 4a Bur 19 20a 79 15 16 17 3a 3a 3f But Bur Ph 21a(Hal = Br) 21b(Hal = I) 21a 22a 22b 22c 78 65 Mb 18 3f Ph 21b 22d 76 ~ ~~ ~ ~ ~~ ~ ~ ~ ~~~~~~~ ~~ ~ ~~ " Yield refers to isolated compound based on unrecovered salt 3 or 4, unless otherwise indicated.Triphenylbismuthine was additional product isolated in 77-97 yields. Determined by 'H NMR. 0.21 (9H,s), 1.02(6H,d, J6.9),2.20(1 H,sept, J6.9),3.97(1 H, 1474, 1437, 1200-950 (BF,), 731,695 and 450; m/z (FAB) 539 S) and 4.04 (1 H, s). 2e, b.p. 86-88 "C (lit.,,' 100 "C); 6, 0.21 (9 (M+ -BF,), 363, 286 and 209 (Found: C, 45.8; H, 4.1. H, s), 1.78 (3 H, s) and 4.05 (2 H, s).2f, b.p. 117-1 19 "C/27-28 C24H26BBiF40requires C, 46.0; H, 4.2). mmHg (lit.,,' 82 "C/5DHg); 8, 0.20 (9 H, s), 4.45 (1 H, d, J (3-Methyl-2-oxobutyl)triphenylbismuthoniumtetrafluoro-1.7),4.93(1H,d,J1.7),7.267.40(3H,m)and7.59(2H,m).2g, borate 3d. M.p. 156157OC (99); 6, 1.18 6 H, d, J 6.9, b.p. 79-81 "C/0.4mmHg; 6, 0.26 (9 H, s), 4.44 (1 H, d, J 1.8), CH(CH,),, 3.01 l H, sept, J 6.9, CH(CH,),, 5.44 (2 H, s, 4.90 (1 H, d, J 1.8) and 7.45 (4 H, s). BiCH,), 7.55-7.66 (9 H, m, Ph) and 7.68-7.82 (6 H, m, Ph); 6c 18.4,41.4,56.7 (BiCH,), 131.9, 132.0, 135.8, 137.8 (BiCipso) and Synthesis of (2-Oxoalkyl )triarylbismuthonium Te trafluoro- 210.4; v,,,(KBr)/cm-' 3050-3000, 1690 (M),1474, 1429, borates 3.To a stirred solution of triarylbismuth trifluoride 1 1200-950 (BF,), 731,695,521 and 445; m/z (FAB) 525 (M' -(1 -01) in CH,Cl, (5 cm3) at 0 "C was added boron BF,), 363,286 and 209 (Found: C, 44.9; H, 3.9.C,3H,,BBiF,0 trifluoride-diethyl ether (0.12 cm3, 1 mmol). This was followed requires C, 45.1; H, 3.95). after 1 h, by the silyl enol ether 2(1 mmol) and the resulting Acetonyltriphenylbismuthonium tetrafluoroborate 3e. M.p. mixture was stirred for further 10 h at ambient temperature to 145-146 "c(lit.,6 128 "c; decomp.) (95); 6H2.41 (3 H, s, CH,), complete the reaction. The solvent was removed under reduced 5.35 (2 H, s, BiCH,), 7.55-7.66 (9 H, m, Ph) and 7.68-7.82 (6 H, pressure to leave an oily residue, which was purified by m, Ph);dc29.7, 57.7(BiCH2), 131.9,132.0,135.8, 137.5(BiCi,,) recrystallization from diethyl ether CH,Cl, (5 : 1) or by column and 204.5; v,,,(KBr)/cm-' 3050-2950, 1696 (GO),1568, 1474, chromatography on silica gel using CH,Cl, as the eluent to 1429, 1358, 1237, 1200-950 (BF,), 729, 695, 521 and 440; m/z afford (2-oxoalkyl)triarylbismuthonium tetrafluoroborate 3 in (FAB) 497 (M+ -BF,), 363,286 and 209 (Found: C, 43.2; H, the yield given in parentheses.3.3. C21H2,BBiF,0 requires C, 43.2; H, 3.45). (3,3-Dimethyl-2-0x0 butyl) triphenylbismuthonium tetra- Phenacyltriphenylbismuthonium tetrafluoroborate 3i. Pale fluoroborate 3a. M.p. 143-145deg;C (96); 6, 1.26 9 H, s, yellow, m.p. 165-167 "C (97); 6, 5.97 (2 H, s, BiCH,), 7.49 (2 C(CH,),, 5.60 (2 H, s, BiCH,), 7.52-7.67 (9H, m, Ph) and 7.68- H, t, J7.1,Ph),7.5amp;7.70(10H,m,Ph),7.81 (6H,m,Ph)and 56.9(BiCH2), 131.8,131.9,135.8, 8.10 (2 H, d, J 7.1, Ph); dC 56.4 (BiCH,), 129.1, 130.1, 131.9, 7.82(6H,rn,Ph);dc26.9,45.9, 137.9 (BiCipso) and 212.2; v,,x(KBr)/cm-l 3050-2950, 1674 132.0, 132.6, 135.1, 135.9, 137.7 (BiCips0) and 195.2; v,,,(KBr)/ (C==O), 1475, 1437, 1150-950 (BF,), 727, 695 and 441; m/z cm-' 3050-2950, 1682 (M),1568, 1474, 1428, 1279, (FAB) 539 (M+ -BF,), 363,286 and 209 (Found: C, 45.8; H, 1200-950 (BF,), 731,693,521 and 450; m/z (FAB) 559 (M+ -4.1.C,,H,,BBiF,O requires C, 46.0; H, 4.2). BF,), 363, 286 and 209 (Found: C, 48.1; H, 3.3. c26-tetrafluoro-H,,BBiF,O requires C, 48.3; H, 3.4). (3-Methyl-2-oxopenty1)triphenylbismuthonium borate3b. M.p. 94-96 "C ();a, 0.85 (3 H, t, J7.5, CH,CH,), (4-Bromophenacyl)triphenylbismuthonium tetrafluoroborate 1.18 (3 H, d, J7.0, CHCH,), 1.40-1.80 (2 H, m, CH,CH,), 2.90 3g.Pale yellow, m.p. 65-67 "C (94); 6, 5.89 (2 H, s, BiCH,), (1 H, sext, J6.7, CH), 5.37 (1 H, d, J 15.0, BiCH,), 5.59 (1 H, d, 7.5amp;7.87(17H,m,PhandAr)and7.97(2H,d, J8.5,Ar);bC J 15.0, BiCH,), 7.25-7.66 (9 H, m, Ph) and 7.68-7.82 (6 H, m, 55.7 (BiCH,), 131.6, 132.0, 132.1, 132.5, 132.5, 133.4, 135.9, Ph); 6, 11.2, 15.6, 26.0,47.8, 57.0 (BiCH,), 131.8, 131.9, 135.8, 137.7 (BiCjpso) and 194.5; v,,,(KBr)/cm-' 3050-2950, 1696 1586, 1474, 1401, 1200-950 (BF,), 781, 729, 685, 521 137.8 (BiCjpso) and 210.2; v,,,(KBr)/cm-' 3050-3000, 1688 (M), 1568, 1474, 1429, 1200-950 (BF,), 727, 695, 523 and and 442; m/z (FAB) 639 (M' -BF,, "Br), 637 (M' -BF,,(M), 446; m/z (FAB) 539 (M+ -BF,), 363,286 and 209 (Found: C, 79Br), 363, 286 and 209 (Found: C, 43.15; H, 2.9.45.9; H, 4.2. C2,H,6BBiF,0 requires C, 46.0; H, 4.2). C2,H2 BBiBrF,O requires C, 43.1 ;H,2.9). tetrafluoro-(3,3-Dimethyl-2-oxobutyl)tri(p-tolyl)bismuthonium(4-Methyl-2-oxopenty1)triphenylbismuthonium tetra-borate 3c. Glass (95); 8, 0.87 6 H, d, J 6.6, CH(CH,),, 2.12 fluoroborate 3h. M.p. 97-98 "C (93); 6, 1.25 9 H, s, C(CH,),, l H, sept, J6.7, CH(CH,),, 2.64(2 H, d, J6.8, CH,CH), 5.32 2.40 (9 H, s, ArCH,), 5.50 (2 H, s, BiCH,), 7.40 (6 H, d, J 8.1, (2 H, s, BiCH,), 7.55-7.68 (9 H, m, Ph) and 7.70-7.82 (6 H, m, ArH) and 7.61 (6 H, d, J 8.1, ArH); S, 21.5, 26.8, 45.8, 55.1 Ph); dC22.3,24.9, 50.8, 57.4 (BiCH,), 131.8, 131.9, 135.8, 137.8 (BiCH,), 132.5, 134.0, 135.5, 142.5 (BiCipw) and 212.2; (BiCipso) and 206.4; v,,,(KBr)/cm-' 3050-2900, 1684 (C=O), v,,,(KBr)/cm-' 3020-2850, 1682 (W),1487, 1387, 1200-950 J.CHEM. SOC. PERKIN TRANS. 1 1994 (BF,), 793 and 480; m/z (FAB) 581 (M+ -BF,), 391,300 and 209 (Found: C, 48.2; H, 4.9. CZ7H3,BBiF,O requires C, 48.5; H, 4.8). (3-Methyl-2-oxopentyl)tri(p-tolyl)bismuthonitun tetrafluoro-borate 3i. M.p. 142-144deg;C (90); 6, 0.85 (3 H, t, J 7.4, CH,CH,), 1.16 (3 H, d, J 6.9, CHCH,), 1.40-1.85 (2 H, m, CH,CH3), 2.41 (9H, s, ArCH,), 2.90(1 H, sext, J6.7, CH), 5.26 (1 H,d, J15.0,BiCH2), 5.39(1 H,d, J15.0,BiCH2),7.40(6H,d, J8.0,ArH)and7.61 (6H,d,J8.0,ArH);dC11.3, 15.7,21.5,26.1, 48.0, 55.3(BiCH2), 132.5,134.0,135.6, 142.6(BiCi,,)and210.3; v,,(KBr)/cn-' 3050-2850, 1694 (GO),1487, 1387, 1200-950 (BF,), 791,521 and 480; m/z (FAB) 581 (M+ -BF,), 391,300 and 209 (Found: C, 48.8; H, 4.7.CZ7H3,BBiF,O requires C, 48.5; H, 4.8). (4-Methyl-2-oxopentyl)tri(p-tolyl)bismuthoniumtetrafluoro-borate 3j. M.p. 58-60 "C (94); BH 0.87 6 H, d, J 6.6, CH(CH,),, 2.12 l H, sept, J 6.7, CH(CH,),, 2.40 (9 H, s, ArCH,), 2.65 (2 H, d, J 6.9, CH,CH), 5.22 (2 H, s, BiCH,), 7.39 (6H, d, J8.l,ArH)and7.61 (6H,d, J8.1,ArH);dC21.5,22.3, 24.9,51.0, 55.8 (BiCH,), 132.5, 133.8, 135.6, 142.5 (BiCipso) and 206.4; v,(KBr)/cm-' 3050-2850, 1688 (GO), 1489, 1391, 1200-950 (BF,), 793, 521 and 475; m/z (FAB) 581 (M' -BF,), 391, 300 and 209 (Found: C, 48.3; H, 4.7.C27- H,,BBiF,O requires C, 48.5; H, 4.8). Phenacyltri(p-toly1)bismuthonium tetrafluoroborate 3k. M.p. 142-144 "C (87);6,2.41(9 H, s, ArCH,), 5.87 (2 H, s, BiCH,), 7.41 (6 H, d, J 7.8, ArH), 7.43-7.75 (9 H, m, Ph and ArH) and 8.11(2H,d,J7.3,Ph);6,21.5,54.8(BiCH,),129.1,130.1,132.6, 133.9, 134.7, 135.1, 135.6, 142.6 (BiC,,,,) and 195.2; v,,,-(KBr)/cm-' 3050-2800, 1685 (GO),1487, 1449, 1200-950 (BF,), 793,743,689,480 and 473; m/z (FAB) 601 (M' -BF,), 391, 300 and 209 (Found: C, 50.6; H, 4.0. C29Hz8BBiF,0 requires C, 50.6; H, 4.1). Synthesis of (2-0xoalkyl)triarylbismuthoniumTriJEuorometh-anesulfonates 4.-These compounds were prepared according to the above procedure, using trimethylsilyl trifluorometh- anesulfonate (0.19 cm3, 1 mmol) in place of boron trifluoride- diethyl ether.Recrystallization of the crude product from Et20-CH2C12 (5: 1) gave compound 4 as colourless crystals. (3,3-Dimethyl-2-oxobutyl)triphenylbismuthonium triJEuoro-methanesulfonate 4a. M.p. 152-154 "C (95); dH 1.28 9H, s, C(CH,),, 5.64 (2 H, s, BiCH,), 7.52-7.65 (9 H, m, Ph) and 7.70-7.80 (6 H, m, Ph);6, 26.9,45.8,58.6 (BiCH,), 131.8,131.9, 135.8, 139.0 (BiCipso) and 212.0; v,,,(KBr)/cm-' 3050-2900, 1674 (GO),1478, 1437, 1320-1220 (OTf), 1200-1120 (OTf), 1030,994,723 and 685; m/z (FAB) 539 (M' -OTf), 363,286 and 209 (Found: C, 43.45; H, 3.75. C2,H26BiF,04S requires C, 43.6; H, 3.8). (3-Methyl-2-oxopentyl)triphenylbismuthoniumtriJEuoro-methanesulfonate 4b. M.p. 117-1 18 OC (93); 6,0.85 (3 H, t, J 7.4, CH,CH,), 1.17 (3 H, d, J6.9, CHCH,), 1.40-1.80 (2 H, m, CH,CH,), 2.88 (1 H, sext, J 6.8, CH), 5.38 (1 H, d, J 15.8, BiCH,), 5.50 (1 H, d, J 15.8, BiCH,), 7.52-7.65 (9 H, m, Ph) and 7.70-7.80 (6 H, m, Ph); 6, 11.3, 15.7, 26.1, 48.1, 58.3 (BiCH,), 131.8, 131.9, 135.8, 137.5 (BiCipso) and 210.1; v,,,(KBr)/cm-l 3050-2900, 1688 (GO), 1429, 1320-1220 (OTf), 1200-1130 (OTf), 1034,729 and 695; m/z(FAB) 539 (M' -OTf), 363,286 and 209 (Found: C, 43.3; H, 3.6.CZ5Hz6BiF30,S requires C, 43.6; H, 3.8). (3,3-Dimethyl-2-oxobutyl)tri@-tolyl)bismuthonium tripuoro-methanesulfonate 4c. M.p. 55-57 "C (88); BH 1.25 9 H, s, C(CH,),, 2.40 (9 H, s, ArCH,), 5.55 (2 H, s, BiCH,), 7.38 (6 H, d, J7.9, ArH)and7.62(6H,d, J7.9, ArH);S,21.5,26.8,45.8, 56.5 (BiCH,), 132.4, 134.7, 135.5, 142.3 (BEipso) and 212.0; v,,,(KBr)/cm-' 3050-2900,1682(GO),1487,1389,1320-1 220 (OTf), 1200-1130 (OTf), 1032, 792 and 660; m/z (FAB) 581 (M+ -OTf), 391, 300 and 209 (Found: C, 45.8; H, 4.3.C,,H,,BiF,O,S requires C, 46.0; H, 4.4)). (3-Methyl-2-oxopentyl)tri(p-tolyl)bismuthoniumtrifloro-methanesulfonate 4d. M.p. 127-128 "C (86); BH 0.84 (3 H, t, J 7.4, CH,CH,), 1.16 (3 H, d, J6.9, CHCH,), 1.40-1.80 (2 H, m, CH2CH3), 2.41 (9 H, s, ArCH,), 2.89 (1 H, sext, J6.7, CH), 5.27 (1 H,d, J15.0,BiCH2),5.39(1 H,d, J15.0,BiCH2),7.40(6H,d, J8.1, ArH) and 7.61 (6 H, d, J8.1, ArH);6,11.3,15.6,21.5,26.1, 48.2,56.7 (BiCH,), 132.4,132.8,135.6,142.4 (BiC,,,) and 210.2; v,,,(KBr)/cm-' 3 100-2900, 1694 (GO), 1489, 1320-1220 (OTf), 1200-1120 (OTf), 1030, 791 and 639; m/z (FAB) 581 (M' -OTf), 391, 300 and 209 (Found: C, 46.1; H, 4.3.C28H,,BiF,04S requires C, 46.0; H, 4.4). NMR Monitoring of the Reaction of the Difluoride la with the Silyl En01 Ether 2a in the Presence of BF,*OEt,.-Into a CDCl, solution (0.5 an3)of the difluoride la (48 mg, 0.1 mmol) in an NMR sample tube was added BF,*OEt, (0.012 cm3, 0.1 mmol) at 0 "C under argon and the solution was examined by 'H and I3C NMR spectroscopy. The silyl enol ether 2a (17 mg, 0.1 mmol) was then introduced into the tube and the resulting solution was examined similarly. The formation of product 3a and fluorotrimethylsilane was quantitative, no other products being observed. Synthesis of Oxybis(triary1bismuth) Bis(triJluoromethane- sulfonate) 5.-To a well stirred solution of the triarylbismuth difluoride 1 (1 mmol) in dichloromethane (5 cm3) at 0 "C was added trimethylsilyl trifluoromethanesulfonate(0.19 cm3, 1 mmol).After 1 h hexamethyldisiloxane (0.1 1 cm3, 0.5 mmol) was added to the mixture and stirring was continued for further 24 h at ambient temperature to complete the reaction. The solvent was removed under reduced pressure to leave an oily residue, which was purified by recrystallization from CH,Cl, to give oxybis(triary1bismuth) bis(trifluor0- methanesulfonate) as colourless crystals. Oxybis(tripheny1bismuth) bis(triJEuoromethanesulfonate)5a. M.P. 205-206 "C (95); amp;(CDCI,-CD3OD, 10: 1) 7.65 (6 H, t, J7.3), 7.79 (12 H, t, J7.5) and 7.99 (12 H, d, J7.6); amp;(CDCl,- CD,OD, 1O:l) 132.7, 133.0, 134.4 and 150.1 (BiCips0) v,,(KBr)/m-' 3100-2900, 1561, 1470, 1330-1 120, 1030, 986, 725 and 635 (Bi-O-Bi); m/z (FAB) 592, 363, 286 and 209 (Found: c, 37.8; H, 2.5.C38H30BiZF607S2 requires c, 38.2, H, 2.5). Oxybistri(p-toly1)bismuthl bis(triJluoromethanesulfonate) 5b.M.p. 199-20OoC(96);6H2.43(18H,~),7.33(12H,d,J8.2) and 7.58 (12 H, d, J 8.2); dC21.5, 132.5, 133.7, 143.0 and 150.9 (BiCipso); v,,(KBr)/cm-' 1485, 1304, 1233, 1215, 1188, 1168, 1022,790,675,637 (Bi-O-Bi) and 473; m/z (FAB) 634,391,300 and 209 (Found: C, 41.4; H, 3.3. C44H42Bi2F607S2 requires C, 41.3, H, 3.3). Reaction of Compound 3f with Triphenylphosphine 6.-A mixture of compound 3f (162 mg, 0.25 mmol), triphenyl- phosphine 6 (65 mg, 0.25 mmol) and CHzC12 (5 cm3) was stirred at room temperature for 24 h, during which time colourless crystals were gradually precipitated- The crystals were filtered off, washed with CH,Cl, (5 cm3 x 2), and dried in uacuo to give phenacyltriphenylphosphoniumtetrafluoroborate 7 (1 1 1 mg, 95).The filtrate was concentrated under reduced pressure to leave an oily residue, which was recrystallized from MeOH to give triphenylbismuthine 8(107 mg, 97). Compound 7,m.p. 249-250 "C; 6,('H,-dimethyl sulfoxide) 6.19 (2 H, d, Jp-H 13.1, CH,), 7.61 (2 H, t, J7.7, Ph), 7.70-7.92 (16 H, m, Ph) and 8.09 (2 H, d, J 7.7, Ph); 6,-(2H6-dimethyl sulfoxide) 35.2 (d, Jpx, 61.7), 119.1 (d, Jpx 88.8), 129.1, 129.2, 130.1 (d, Jpx 12.9), 133.8 (d, Jpx10.8), 134.9, 135.1, 135.2 and 192.3 (d, Jpx 6.2); v,,,(KBr)/cm-' 1669, 1593, 1439, 1327, 1302, 1204, 1150- 1000, 995, 747, 720, 689 and 515 (Found: C, 66.3; H, 4.7.C2,H,,BF40P requires C, 66.7; H, 4.7). Reaction of Compound 3f with Dimethyl Surfide 9.-To a solution of compound 3f (162 mg, 0.25 mmol) in CH,Cl, (5 cm3) was added dimethyl sulfide 9 (0.18 cm3, 2.5 mmol) at room temperature. Colourless crystals were immediately precipitated. Work-up as described above gave dimethylphenacylsulfonium tetrafluoroborate 10 (65 mg, 97) and the bismuthine 8 (108 mg, 98). Compound10, m.p. 169-170 "C (lit.,,, 168.5-170 "C); 6H(2H6-dimethyl sulfoxide) 2.95 (6 H, s, CH,), 5.42 (2 H, s, CH,), 7.64 (2 H, t, J7.7, Ph), 7.79 (1 H, t, J 7.4, Ph) and 8.03 (2 H, d, J 7.7, Ph); 6,(2H6-dimethyl sulfoxide) 23.4, 51.7, 127.3,127.9,132.5,133.8 and 190.0; v,,,(KBr)/m-' 1682,1599, 1456,1431,1341,1331,1318,1217,1150-950,756,689,637and 523.Reaction of (2-Oxoalkyl)triphenylbismuthoniumSalts 3 with the Sodium EnoZate 11.-To a suspension of the bismuthonium salt 3 (0.8 mmol) in THF (2 an3)cooled down to -50 "C was added a solution of the sodium enolate 11,generated from well- washed sodium hydride (ca. 19 mg) and dibenzoylmethane (1 79 mg, 0.8 mmol) in the same solvent (3 an3).The resulting yellow solution was stirred for 10 h during which time the temperature was gradually raised to ambient. The colourless mixture was then concentrated under reduced pressure and extracted with diethyl ether (1 5 cm3).Removal of the solvent afforded an oily residue, which was subjected to silica-gel column chromato- graphy with hexane-ethyl acetate as the eluent to give the corresponding tricarbonyl compound 12 and triphenylbis-muthine 8. 2-Benzoyl-5-methyl-1 -phenyZhexane-l,4-dione 12a. M.p. 92- 93 "C; 6, 1.16 6 H, d, J7.0, CH(CH,),, 2.74 l H, hept, J 7.0, CH(CH,),, 3.22 (2 H, d, J 6.5, CHCH,), 5.91 (1 H, t, J 6.5, CHCH,), 7.45 (4 H, t, J7.3, Ph), 7.57 (2 H, t, J7.3, Ph) and 7.97 (4 H, d, J7.3, Ph); v,,,(KBr)/cm-' 1696,1671, 1595,1449, 1273, 1238, 1000, 756 and 708; m/z (EI) 265 (M' -43), 105 and 77 (Found: C, 78.3; H, 6.3. C20H20O3 requires C, 77.9; H, 6.5). 2-Benzoyl-l,4-diphenylbutane-l,4-dione12b. M.p.148-149 "C (lit.,,, 99-100 "C);6H 3.78 (2 H, d, J6.4, CHCH,), 6.13 (1 H, t, J6.4,CHCH2),7.44(6H,t,J7.3,Ph),7.57(3H,t,J7.2,Ph)and 7.98-8.05 (6 H, m, Ph); v,,,(KBr)/cm-' 1686, 1669, 1595, 1449,1277,1221,1000 and 685; m/z (EI) 237 (M+ -105), 220, 105 and 77 (Found: C, 80.5; H, 5.25. C23H1@3 requires C, 80.7; H, 5.3). Reaction of Compound 3f with Piperidine 13.-To a solution of compound 3f (162 mg, 0.25 mmol) in CH2C12 (5 cm3) was added piperidine (85 mg, 1.0 mmol) and the resulting mixture was stirred for 6 h at room temperature. The reaction mixture was filtered over a Celite and the filtrate was concentrated under reduced pressure to leave a mixture of unchanged amine 13, a-piperidino ketone 14 and triphenylbismuthine 8 as an oily residue.Products were identified by comparison with the authentic specimens. 24 Reactions of (2-0xoaZkyl)triphenylbismuthoniumSalts 3 and 4 with Sodium Aryl Oxides 15or Arenethiolates 17.-To a well stirred suspension of the bismuthonium salt 3or 4 (0.8 mmol) in THF (2 cm3) at -50 "C was added a solution of the sodium aryl oxide 15 or arenethiolate 17 in the same solvent (3 cm3) generated from well-washed sodium hydride (ca. 19 mg) and hydroxyarene or arenethiol (0.8 mmol). The resulting yellow solution turned colourless after 1 h under gentle reflux in the former case, and upon warming to room temperature in the latter. The mixture was concentrated under reduced pressure and extracted with diethyl ether (15 cm3). Removal of the solvent from the extract afforded an oily residue, which was J.CHEM. SOC.PERKIN TRANS. 1 1994 purified by column chromatography on silica gel using hexane- ethyl acetate as the eluent to give the corresponding a-aryloxy- or a-arylthio-ketone 16 or 18and triphenylbismuthine 8. 3,3-Dimethyl-1-phenoxybutan-Zone 16a. M.p. 4445 "C (lit.,,' 46 "C); 6, 1.24 9 H, S, C(CH,)J, 4.86 (2 H, S, OCH,), 6.87 (2 H, d, J7.6, Ph), 6.97 (1 H, t, J7.3, Ph) and 7.27 (2 H, t, J 7.5, Ph); v,,,(KBr)/cm-' 1725, 160 1, 1497, 1 370, 13 10, 1229, 1175, 1049, 990, 754 and 691; m/z (EI) 192 (M'), 149, 107, 85 and 77 (Found: C, 74.9; H, 8.4. C12H1602 requires C, 75.0; H, 8.4). 3,3-Dimethyl- 1 -naphthyloxybutan-2-one 16b. M.p. 56-57 "C (lit.,,' 80-81 "C);6, 1.27 9 H, S, C(CH,)J, 5.01 (2 H, S, OCH,), 6.63 (1 H, d, J7.6,Ar), 7.31 (1 H, t, J7.9, Ar), 7.42-7.45(3 H,m, Ar), 7.78 (1 H, m, Ar) and 8.38 (1 H, m, Ar); v,,,(KBr)/m-l 1728,1582,1509,1460,1393,1271, 1242,1090,1061, 1019,789 and 766; m/z (EI) 242 (M'), 158, 157,127, 115 and 57 (Found: C, 79.3; H, 7.3.C16H18O2 requires C, 79.3; H, 7.5). 1-(4-Chlorophenoxy)-3,3-dimethylbutan-2-one16c. M.p. 61- 62 "C (lit.,25 62 "C); 6, 1.23 9 H, S, C(CH,)J, 4.84 (2 H, S, OCH,), 6.79 (2 H, d, J9.0, Ar) and 7.21 (2 H, d, J9.0, Ar); v,,,(KBr)/cm-' 1719, 1595, 1579, 1491, 1435, 1285, 1246, 1051, 994,824,801 and 654; m/z (EI) 228 (M', ,'Cl), 226 (M+,35Cl), 141, 139, 113, 111, 85 and 57 (Found: C, 63.3; H, 6.8. C,,H,,ClO, requires C, 63.6; H, 6.7). 3.3-Dimethyl-1-phenylthiobutan-2-one18a. Oil (lit.,26 b.p.112-1 14 "C/O. 1 mmHg); 6, 1.19 9 H, S, C(CH,),, 3.95 (2 H, S, SCH,) and 7.15-7.45 (5 H, m, Ph); v,,,(neat)/cm-' 1707, 1582, 1478, 1439, 1059, 1024,999 and 739; m/z (EI) 208 (M'), 125, 123, 109,85 and 77 (Found: C, 68.9; H, 7.6. C12H160S requires C, 69.2; H, 7.7). 144-Chlorophenylthio)-3,3-dimethylbutan-2-one18b. M .p. 42-43 "C (lit.,,' 42 "C);6, 1.18 9 H, S, C(CH,),, 3.92 (2 H, S, SCH,), 7.24 (2 H, d, J 8.9, Ar) and 7.32 (2 H, d, J 8.9, Ar); v,,,(KBr)/cm-' 1707, 1477, 1391, 1366, 1096, 1059, 1013 and 822; m/z (EI) 244 (M', 37Cl), 242 (M+, 35Cl), 159,157,85 and 57 (Found: C, 59.4; H, 6.3. Cl2HlsC1OS requires C, 59.4; H, 6.2). Reaction of (2-Oxoalkyl)triphenylbismuthoniumSalts 3 or 4 with Sodium Toluene-p-sulJinate 19.-A mixture of compound 3 or 4 (0.3 mmol), hydrated sodium toluene-p-sulfinate 19 (750 mg, 3 mmol) and DMF (5 cm3) was stirred at room temperature for 24 h and then poured into water (1 0 cm3). The organic layer was extracted with diethyl ether (10 cm3 x 3) and the combined extracts were washed with brine (10 cm3 x 3), dried (MgS04) and concentrated under reduced pressure to leave a crystalline residue, which was purified by column chromatography on silica gel using hexan-thy1 acetate as the eluent to give the a-sulfonyl ketone 20 and triphenylbismuthine 8.3,3-Dimethyl-l-(p-tolylsulfonyl)butan-2-one2Oa. M.p. 113-114 "C; 6, 1.1 1 9 H, S, C(CH3),, 2.44 (3 H, S, ArCH,), 4.33 (2 H,s,SO2CH2),7.36(2H,d,J8.4,Ar)and7.82(2H,d,J8.4,Ar); v,,,(KBr)/m-' 1717,1595,1370,1320,1291,1167,1140,1055, 884, 756, 556 and 515; m/z (EI) 170, 155, 105, 91, 65 and 57 (Found: C, 61.2; H, 7.1.C13H180,S requires C, 61.4; H, 7.1). 1-Phenyl-2-(p-tolylsulfonyZ)ethanone20b. M.p. 106-1 07 "C (lit.,,' 105.5-106.5 "C); dH2.43 (3 H, S, ArCH,), 4.72 (2 H, S, SO,CH,), 7.32(2H,d, J8.3,Ar), 7.46(2H, t, J7.7,Ph),7.61 (1 H, t, J7.6,Ph),7.76(2H,d, J8.3,Ar)and7.94(2H,d, J7.8,Ph); v,,,(KBr)/cm-' 1680, 1597, 1449, 1320, 1271, 1150, 1086, 994, 824,739,693,590,534 and 502; m/z (EI) 210,155,149,105,91, 77 and 65. Reaction of (2-Oxoalkyl)triphenyZbismuthoniumSalts 3 with Potassium Halides 21.-A mixture of compound 3 (1 mmol), potassium halide 21 (10 mmol) and DMF (5 cm3) was stirred at room temperature for 24 h and then poured into water (10 cm3).The organic layer was extracted with diethyl ether (10 cm3 x 3) J. CHEM. SOC. PERKIN TRANS. 1 1994 and the combined extracts were washed with brine (10 cm3 x 3), dried (MgSO,) and concentrated under reduced pressure to leave a mixture of the a-halogeno ketone 22 and triphenylbismuthine 8 as an oily residue. Products were identified by comparison with the authentic specimens. X-Ray Crystallography of Compounh 3a, 4a and 5a.-Inten-sity data were recorded on a Rigaku AFC5R diffractometer with graphite-monochromated MoKa radiation and a 12 kW rotating anode generator using the 0-28 scan technique to a maximum 20-value listed in Table 1. Data were corrected for Lorentz and polarization effects. The structure was solved by a combination of the Patterson method and direct methods.28 The non-hydrogen atoms were refined anisotropically.The weighting scheme, w = l/02(Fo), was employed. Neutral atom- 10 B. A. Arbuzov, Y. V. Belkin, N. A. Polezhaeva and G. E. Buslaeva, Izv. Akad. Nauk SSSR, Ser. Khim., 1978, 1643. 11 Y. Matano, N. Azuma and H. Suzuki, Tetrahedron Lett., 1993,34, 8457. 12 B. K. Hunter and L. W. Reeves, Can. J. Chem., 1968,46, 1399. 13 R. G. Goel and H. S. Prasad, J. Organomet. Chem., 1972,36,323. 14 J. Border and L. D. Freedman, Phosphorus, 1973,3 33. 15 D. H. R. Barton, B. Charpiot, E. T. H. Dau, W. B. Motherwell, C. Pascard and C. Pichon, Helv. Chim. Acta, 1984,67, 586. 16 A. Bondi, J.Phys. Chem., 1964,68,441. 17 F. C. March and G. Ferguson, J. Chem. SOC.,Dalton Trans., 1975, 1291; G. Ferguson, R. G. Goel, F. C. March, D. R. Ridley and H. S. Prasad, J. Chem. SOC.,Chem. Commun., 1971,1547. 18 D. H. R. Barton and J.-P. Finet, Pure Appl. Chem., 1987,59,937; R. A. Abramovitch, D. H. R. Barton and J.-P. Finet, Tetrahedron, 1988, 44, 3039; D. H. R. Barton, J.-P. Finet, C. Giannotti and F. Halley,J. Chem. SOC.,Perkin Trans. I, 1987,241; D. H. R. Barton, scattering factors Anomalous dispersion effects were included in F,; 30 the values for Aflsquo;and Afrdquo;were those of Cr~mer.~~ All calculations were performed using the TEXSAN 32 crystallographic software package of Molecular Structure Corporation. The PLUTO 33 program was used to obtain Figs.1-3. Crystal data, selected bond lengths and bond angles are given in Tables 1-4. Full details of crystal data, fractional atomic coordinates, bond lengths, bond angles, hydrogen coordinates and thermal parameters of compounds 3a, 4a and 5a have been deposited at the Cambridge Crystallographic Data Centre. * Acknowledgements We acknowledge support of this work by a Grant-in-Aid for Encouragement of Young Scientists, No. 05740392 from the Ministry of Education, Science and Culture. * For details see lsquo;Instructions for Authors (1994)rsquo;, J. Chem. Soc., Perkin Trans I, 1994, Issue 1. References 1 For a general survey of organic bismuth compounds see: L. D. Freedman and G. 0.Doak, Chem. Rev., 1982,82,15; P. G. Harrison, Organomet.Chem. Rev., 1970,s 183; J.-P. Finet, Chem. Rev., 1989, 89, 1487. 2 G. Wittig and K. Clauss, Liebigs Ann. Chem., 1952,578, 136. 3 R. E. Beaumont, R. G. Goeland H. S. Prasad, Inorg. Chem., 1973.12, 944. 4 G. 0.Doak, G. G. Long, S. K. Kakar and L. D. Freedman, J. A4m. Chem. Soc., 1966,88,2342. 5 D. Hellwinkel and M. Bach, Liebigs Ann. Chem., 1968,720, 198. 6 R. G. Goel and H. S. Prasad, J. Chem. SOC.A, 1971,562. 7 R. E. Beaumont and R. G. Goel, J. Chem. SOC.,Dalton Trans., 1973, 1394. 8 Z. El-Hewehi and D. Hempel, J. Prakt. Chem., 1963,22, 1. 9 P. Schipper and H. M. Buck, Phosphorus, 1971,1,93. were taken from Cromer and Wabe~-.~~ J.-P. Finet, W. B. Motherwell and C. Pichon, Tetrahedron, 1986,42, 5627; D. H. R. Barton, J. C.Blazejewski, B. Charpiot, J.-P. Finet, W. B. Motherwell, M. T. B. Papoula and S. P. Stanforth, J. Chem. SOC.,Perkin Trans. I, 1985,2667; and references cited therein. 19 G. Wittig and K. Clauss, Liebigs Ann. Chem., 1952, 578, 136; A. Schmuck,D. Leopold, S. Wallenlauer and K. Seppelt, Chem. Ber., 1990,123,761; A. Schmuck and K. Seppelt, Chem. Ber., 1989,122, 803; A. Schmuck, J. Buschmann, J. Fuchs and K. Seppelt, Angew. Chem., Int. Ed. Engl., 1987,26, 1180. 20 F. Challenger and J. F. Wilkinson, J. Chem. SOC., 1922, 121,91. 21 D. Cazeau, F. Duboudin, F. Moulines, 0.Babot and J. Dunogues, Tetrahedron, 1987,43,2075. 22 A. L. Maycock and G. A. Berchtold, J. Org. Chem., 1970,352532. 23 T. Ibata, M. Hamaguchi and H. Nishigaki, Chem. Lett., 1976, 1267. 24 M. D. Wang and H. Alper, J. Am. Chem. SOC.,1992,114,7018. 25 C. Rivalle and E. Bisagni, Bull. SOC.Chim. Fr., 1972,2749. 26 P. Brownbridge and S. Warren, J. Chem. Soc., Perkin Trans. 1, 1977,2272. 27 J. P. Weidner and S. S. Block, Synthesis, 1970,583. 28 Structure solution methods: J. C. Calbrese, PHASE-Patterson Heavy Atom Solution Extractor, Ph.D. Thesis, University of Wisconsin-Madison, 1972; P. T. Beurskens, DIRDIF: Direct Method for Difference Structures-an automatic procedure for phase extension and refinement of difference structure factors, Tech- nical Report 1984/1 Crystallography Laboratory, Toernooiveld, 6525 Ed Nijmegen, Netherlands. 29 D. T. Cromer and J. T. Waber, International Tables for X-ray Crystallography, The Kynoch Press, Birmingham, England, 1974, vol. 4, Table 2.2 A. 30 J. A. Ibers and W. C. Hamilton, Acta Crystallogr., 1964, 17, 781. 31 D. T. Cromer, ref. 30, Table 2.3.1. 32 TEXSAN-TEXRAY Structure Analysis Package, Molecular Struc- ture Corporation, 1985. 33 S. Motherwell and W. Clegg, PLUTO. Program for Plotting Molec- ular and Crystal Structures, University of Cambridge, England, 1978. Paper 4/00782D Received 8th February 1994 Accepted 28th February 1994