Reactions of ethoxycarbonylmethylene(triphenyl)phosphorane with someortho-quinones in the presence of triphenylphosphine, alcohols and acetic anhydride

摘要

J. CHEM. SOC. PERKIN TRANS. 1 1992 React ions of Ethoxycarbonylmethylene( triphenyl) phosphorane with some ortho-Quinones in the Presence of Triphenylphosphine, Alcohols and Acetic Anhydride Demetrios N. Nicolaides," Spyros G. Adamopoulos, Demetrios A. Lefkaditis, Konstantinos E. Litinas and Petroula V. Tarantili Laboratory of Organic Chemistry, University of Thessaloniki, Thessaloniki 54006,Greece The reactions of ortho-quinones la, lc and Id with ylide 2 in the presence of triphenylphosphine afforded the ylides Ila, Ilc and Ild and compound 12. The reactions of la and Ic with 2 in refluxing methanol or ethanol gave compounds 16 and 17 respectively, while the reactions of la-d with 2 in acetic anhydride yielded the acetates 18a, 18b, 18d and 19b, 19d, the furan derivative 24 and the ylide 25.Compounds 8 and 9 were also obtained in most of the above reactions. Wittig reactions of ylides Ila, Ilc with p-nitrobenzaldehyde and of ylide 2 with coumarins 8a and 29 resulted in compounds 14a, 14c, 26 and 30 respectively. The transformations of compounds 18, 19 into 8,9 as well as of compound 26 into 28 were also studied. Bestmann and Lang reported' in 1969 that the reactions of ortho-quinones la-b and of 4-anilino- 1,2-naphthoquinone with ethoxycarbonylmethylene(tripheny1)phosphorane2,as well as with its methoxy analogue, afford the corresponding 4-alkoxy- carbonylcoumarins 8, via the suggested intermediates 3,4,6, depicted in Scheme 1. Recently Soliman et af. reported that reaction of the same ylides with benzoaphenazine-8,9-dione gives the corresponding dialkyl 1,2-dihydrofuro- 1,2-dicarboxy- lates 5, again via intermediates 3and 4.Very recently we found that the reactions of 2with o-quinones la-d in dichloromethane solutions afford, besides the coumarins 8a4,the y-lactones 9b and 9c,the hydroxy derivatives 6d (33) and 12(8) and the ylide llc (373, according to the mechanisms proposed in Scheme I.We also found that, when the reactions between 2 and la-are carried out in ethyl vinyl ether solution and the ylide 2 is added portionwise into the reaction mixture, the intermediates o-quinone methanides 3a, 3b, 3d are trapped by the dienophile to give the corresponding cis-and trans-pyran derivatives 20a, 20b, 20d in a high total yield.Similarly, the 2-methyl-2-phenyl disubstituted pyran derivative was also ob- tained as the main product from the reactions between la and 2 in the presence of x-methylstyrene, whereas 4-acyl- or 4-benzoyl- substituted pyrans were obtained from the reactions between la and the ylides Ph,P=CHCOR (R = Me, Ph) in ethyl vinyl ether s~lution.~These results show that the corresponding Wittig monoolefination products initially formed can be trapped easily and under mild conditions by dienophiles, as can the other known o-quinone methanides,' though these intermediates are also very reactive towards the starting ylides used and the triphenylphosphine, generated in situ. In connection with these studies we now report our results on the reactions of the ylide 2 with some n-quinones, performed (a) in the presence of an excess of triphenylphosphine; (b) in refluxing methanol or ethanol and (c) in hot acetic anhydride solutions.Furthermore, the reaction between la or 8aand 2at high temperature, the Wittig reaction of ylides 1la and 1 lc,prepared for reactions (a), as well as some transformations of the triesters 18and 19,are reported. Results and Discussion The title reactions studied and the products obtained are depicted in Schemes 1-3. To a stirred dichloromethane solution of a mixture of quinone la (1 equiv.) and triphenylphosphine (3 equiv.), the ylide 2 (1 equiv.) was added at room tempera- ture and portionwise, during 2 h. The mixture was then stirred for further 20 h at ambient temperature and was afterwards heated at reflux for 48 h to give, on cooling, crystals of 3- (triphenylphosphoranylidene)phenanthro9,lO-bfuran-2( 3H)-one6 lla in 79 yield.The reaction between lc, triphenyl-phosphine and ylide 2 (added during 4 h) for 24 h at room temperature afforded, after separation of the reaction mixture by column chromatography 5,7-di-tert-butyl-3-triphenylphos-phoranylidenebenzobfuran-2(3H)-one 1lc (49), along with ethyl 6,8-di-tert-butyl-2-oxo-2H-chromene-4-carboxylate 8c (1 2) and 5,7-di-rert-butyl-3-ethoxycarbonylmethylene-benzobfuran-2(3H)-one 9c (6). When the reaction was carried out by immediate addition of the ylide 2and the reaction mixture was then stirred for 45 h at room temperature, the ylide llc was obtained in 60 yield.Compounds lla and llc are identical with those prepared previously in 63 and 58 yield respectively'under dry conditions and nitrogen atmosphere from the reactions of quinones la and lc with (2,2-di-ethoxyviny1idene)triphenylphosphorane and triphenylphos-phine. The tetrachloroquinone Id proved to react with triphenylphosphine under the conditions described above. Thus, when triphenylphosphine was added to a dichloro-methane solution of Id, an exothermic reaction took place immediately and before addition of the ylide, finally yield- ing tetrachlorocatechol 13 (690/,), obviously via the further hydrolysis of the initially formed triphenyldioxaphospholene intermediate. The quinone la reacts with triphenylphosphine in a similar way, but at a higher temperature (70 '-C).' When the quinone Id was added portionwise to a stirred dichloromethane solution of equimolar amounts of triphenylphosphine and of ylide 2and the reaction mixture was stirred for further 24 h at room temperature and then subjected to column chromato- graphy, compound 13 (1373, ethyl (3,4,5,6-tetrachloro-2-hydroxypheny1)acetate 12 (3779 and 4,5,6,7-tetrachloro-3-triphenylphosphoranylidenebenzobfuran-2(3H)-one 1Id (2) were obtained.Although this experimental procedure leads again to the formation of the desired o-quinone methanide 3d and further to its trapping by triphenylphosphine, the betaine thus produced is mainly hydrolysed to the hydroxy derivative 12,prior to the expected lactonization to the stable ylide 1Id.A possible explanation for the predominant formation of com- pound 12 to compound lld, suggested by a referee, is that the electron withdrawing effects of the four chlorine substituents in 10d reduce the electron density of the phenoxy anion, thereby rendering it less nucleophilic.A similar electronic effect can also explain the reported isolation of the hydroxy derivative 6d (in 33 yield) and the carbonyl absorption of compound lld at v/cm-' 1710. It should be noted that the same C=O bond in 284 J. CHEM. SOC. PERKIN TRANS. I 1992 R' R' F' R2)$ R3 R4 + Ph3P=CHC02Et 2 R2* R3 wlH H Et C02Et R4 CO2Et + R3 @ CHC02Et led 9 b,c to(a --EtOH -EtOH r R' -Ph3P __c 0 II0 6 a4 7b-d Ac~O 1 R' -0 + R2amp;co2EtR3 17 $ C02Et 15 18 a, b, d 19 b, d 10 a, c,d -EtOHI CI OH R3R2* Et CI R4 C02Et 11 a, c, d 12 16 13 20 a, b, d for 11 a.c 14 a, c (I+ II) Scheme 1 compounds lla and llc appeared6 at v/cm-' 1680. The butyl-3-(4-nitrobenzylidene)benzofuran-2(3~)-ones 14c, (38) recorded spectral data for compound 1Id are in agreement with and 14c1, (49) were isolated. All these Wittig products the suggested ylide form. exhibited the carbonyl band in the range v/cm-' 1765-1780, 3H)ones8 More Treatment of compound 1la with 4-nitrobenzaldehyde in like other similar 3-alkylidenebenzofuran-2( refluxing dichloromethane for 48 h afforded 3-(4-nitrobenzyl- evidence is necessary for the configurational assignment of the idene)phenanthro9, 10-bfuran-2(3H)-one 14a in 17 yield.products 14 though the 2-configuration seems more favourable When the same reaction was carried out in refluxing toluene, for 14a due to expected reduced steric hindrance. The Wittig compound 14a was again obtained, but in 67 yield. By a reaction of naphtho2,1 -bfuran-l,2-dione with ylide 2 and also similar treatment of ylide llc with 4-nitrobenzaldehyde in a with its methoxy analogue has also been used' for the refluxing dichloromethane solution, the two isomeric 5,7-di-tert- preparation of similar alkyl 2-oxonaphthoC2,l -bfuran- 1(2H)- J. CHEM. SOC. PERICINTRANS. 1 1992 1oa Ph3P=C: COMe -@-H+ COpEtbsol; C-PPh3 I / COpEt 25 21 2 24 Scheme 2 8a 2 26 28 27 m+2 -WH-COzEt 29 30 Scheme 3 ylideneacetates, though recently it has been reported that the reactions of some furan-2,3-diones with the same ylides lead to the Wittig olefination of the lactonic carbonyl and not of the keto carbonyl.' When the reaction of quinone la with ylide 2 was carried out in refluxing methanol and the ylide was added portionwise, the expected" Michael addition of the methanol to the corre- sponding o-quinone methanide intermediate 3a predominated over all the other competing reactions of 3a, leading originally to the formation of ether 15.Thus, to a precipitate of quinone la in refluxing methanol the ylide 2 (1.2 equiv.) was added in portions during 4 h and the reaction mixture was heated at reflux for further 20 h, until all the quinone was consumed, to give, after filtration, crystals of 3-methoxyphenanthr09,10-bfuran-2(3H)-one 16 (31), obviously by further lactonization of the ether 15 initially formed.Separation of the filtrate by column chromatography afforded an additional amount of 16 (17, total yield 48), along with ethyl 2-oxo-2H-dibenzo- f;hchromene-4-carboxylate 8a (35).Treatment of quinone lc with 2 in refluxing methanol resulted in the formation of a mixture of ethyl and methyl derivatives, obviously by part transesterification of the original ethyl derivatives, which were only roughly separated by chromatography and not further studied. After that the reaction of lc with 2 was carried out in refluxing ethanol for 29 h to give ethyl (3,5-di-tert-butyl-2- hydroxypheny1)ethoxyacetate 17 (5), along with compounds 8c (43),9c (5) and llc (4).We next studied the reactions between the quinones lad and the ylide 2 in the presence of acylating agents, in an effort to trap the suggested intermediates 6 and/or 7 by their acylation into the corresponding acetoxy derivatives 18 and/or 19, and to shed more light into the problem concerning the formation and the configuration of the y-lactones 9b and 9c obtained previ~usly.~We note that further lactonization of the ethyl fumarate intermediates 6 could lead to formation of the coumarins 8 and/or to formation of the (E)-y-lactones 9. That was previously suggested by us for compounds 9b and 9c on the basis of their 'H NMR ~pectra.~ Furthermore, the lactonization of the ethyl maleate intermediates 7 could lead only to the formation of the (Z)-y-lactones 9.Although it is known that phosphorus ylides react easily with acylating agents to give at first acyl salts and further on the corresponding acyl ylides, we initially tried the reaction between compounds la and 2 (2 equiv.) in ethyl acetate solution, at room temperature. Separation of the reaction mixture by column chromatography gave only compound 8a (69). Next a solution of quinone la and ylide 2 (2 equiv.) in excess of acetic anhydride, used also as a solvent, was kept at room temperature for 24 h to yield the expected acetoxy compound 18a (28) and compound 8a (53).When the same reaction was carried out at 60deg;C, compounds 18a (62), 8a (25) and the unexpected ethyl 2-methylphenanthro9,l0-bfuran-3-carboxylate24 (7) were obtained.Further transformation of the intermediate 10a (Scheme 1) to the o-hydroxy ylide 21, followed firstly by acetylation of 21 into the ester ylide 22 and then by an intramolecular Wittig reaction of the ylide group with the carbonyl of the ester group l2 of intermediate 22, can account for the formation of the furan derivative 24 (Scheme 2). As an alternative process to compound 24 could also be considered the acylation of 21 to the phosphonium derivative 23, followed by an intramolecular attack of the hydroxy to the acetyl carbonyl of 23 to the same betaine intermediate, as known from the Wittig reaction of 22, and in analogy to the reported previously 'internal Wittig' rea~tion.'~ The intermediate 23 could also be formed by the Wittig monoolefination of quinone la with the stable and less reactiveI4 ylide 25,'lb generated in situ by acetylation of a part of 2, and by further attack of the corresponding o-quinone methanide thus formed, with triphenylphosphine. However, in a control experiment it was found that a mixture of compounds la and 25 remained unchanged, even after reflux for 24 h in chloroform. In agreement with the proposed structure 24 the product under question showed in the 'H NMR spectrum the characteristic low field absorptions for the fused phenanthrofuran system: along with those for the methyl and ethoxycarbonyl sub- stituents, as well as correct molecular ion and analytical data. The reaction between lb, 2 and acetic anhydride at 60 "Cfor 10 h afforded the acetoxy isomers 18b (36) and 19b (23) along with the coumarin derivative 8b (9).When the quinone lc was treated with ylide 2 in acetic anhydride solution under the same conditions, only compounds 8c (4),9c (73) and the ylide 25 (19) were obtained. Probably, the bulky substituent R' (But) in the intermediates 6c and/or 7c prevents the intermolecular attack of the adjacent hydroxy by the acetic anhydride. Finally the reaction between compounds Id and 2 in acetic anhydride afforded compounds 18d (3373, 19d (24) and 25 (27). Compound 18d is identical in all respects with that previously obtained by treatment of the isolated compound 6d with acetic anh~dride.~ The suggested trans-configuration 18a, for the sole acetoxy product, obtained from quinone la, and 18b, 18d for the major acetoxy isomers obtained from quinones lb and Id respectively, is based on the one hand on the fact that in absence of the acetic anhydride only the coumarin 8a and mairly the coumarin 8b are obtained from quinones la and lb, obviously via the further 6-lactonization of the fumarate intermediates 6a and 6b, and on the other hand on the fact that the isolated compound 6d was converted by prolonged heating in refluxing toluene quanti- tatively (89) into the coumarin 8d.3 The recorded chemical shifts for the olefinic proton in the 'H NMR spectra of com- pounds Ma, 18b, 18d and 6d3 are very similar to each other and also to those of y-lactones 9b and 9c, and are quite different from those recorded for the acetoxy maleates 19b and 19d.This observation can be used as an evidence in favour of the (E)-configuration of compounds 9b and 9c, as it was previously suggested by US.^ Furthermore, when an ethanolic solution of compound 18a was heated at reflux for 6 h in presence of hydrochloric acid, it afforded only compound 8a in almost 100 yield. Compound 18d gave, under the same conditions, quantitatively the hydroxy derivative 6d. Unfortunately, both the acetoxy compounds 18b and 19b were found to give, by a similar treatment, both the lactonization products 8b and 9b.When an ethanolic solution of 18b, containing hydrochloric acid, was left to stand at room temperature for 64 h, and the reaction mixture was then separated by column chromato- graphy, compounds 8b (52) and 9b (773, along with some unreacted starting compound 18b (34) were obtained. By a similar treatment of the isomer 19b for only 9 h the starting compound 19b (40), the coumarin 8b (41) and the y-lactone 9b (16), identical in all respects with that obtained from 18b, were isolated from the reaction mixture. Although the con- version of both acetoxy compounds 18b and 19b to the same lactonization products proves beyond any doubt that they are configurational and not peri-isomers, it does not confirm with any certainty the route of formation and the configuration of the compounds under question.It is also of interest to notice once more that the y-lactones 9 were obtained only from quinones withR4 = H. In an unsuccessful effort to trap the intermediate 3a via coumarin 29, we found that dissolution of quinone la in an excess (5 equiv.) of melted coumarin 29 and further portionwise addition of ylide 2 (1.5 equiv.) to the heated mixture led to compound 8a (47) and ethyl (3,4-dihydro-4-ethoxycarbonyl-2H-phenanthro9,10-bpyran-2-yl)acetate 28 (1273, along with triphenylphosphine and triphenylphosphine oxide. No trapping products ' of the intermediate 3a by coumarin 29 were detected or isolated from the reaction mixture. We considered that compound 28 was formed from compound 8a according to the reaction sequence depicted in Scheme 3.In agreement with the above consideration, when a toluene solution of equimolar amounts of compounds 2 and 8a was heated at reflux for 3 days, it gave ethyl (4-ethoxycarbony1-2H-phenanthro9,10-b)pyran-2-y1idene)acetate 26 in 48 yield. Furthermore, a toluene solution of compound 26 and triphenylphosphine (2.5 equiv.) was heated at reflux for 48 h and the reaction mixture was then J. CHEM. SOC. PERKIN TRANS. 1 1992 separated by column chromatography to give compound 28 in 18 yield. Coumarin 29 also reacted with ylide 2, but at higher temperatures. A mixture of equimolar amounts of compounds 2 and 29 was heated at 115-120 "C for 48 h to give ethyl (2H-benzoCblpyran-2-ylidene)acetate30 (35).The recorded spectral data ('H NMR, IR and MS) and the analytical data of the knew compounds of Scheme 3 support the structures proposed for them, although more evidence is necessary for their configurational assignment. It is of interest to notice that the reported reactions of some other lactones with phosphorus ylides did not give the normal Wittig olefination products.'6 It must also be pointed out that attack of triphenylphosphine to the Wittig product 26, and further transformation of the initial phosphonium derivative thus formed to the final product 28, can proceed in more than one step, the bis-ylide 27, depicted in Scheme 3, being one of the possible intermediates. Similar reactions of triphenylphosphine with maleic anhydrides, maleimides and isomaleimides to give the corresponding phosphorus ylides have been known since 1968.'' In conclusion, the reactions between o-quinones and alkoxy- methylene(tripheny1)phosphoranes are of significant synthetic value, since they can be used for the preparation of several different compounds, depending on the particular reagents present and the reaction conditions applied.Experimental M.p.s were determined on a Kofler hot-stage apparatus and are uncorrected. IR spectra were obtained with a Perkin-Elmer 297 spectrophotometer. 'H NMR spectra were recorded with deuteriochloroform as solvent on a Bruker AW 80 (80 MHz) spectrometer with SiMe, as internal standard. Coupling con- stant values, J, are given in Hz.Mass spectra were determined on a VG-250spectrometer with ionization energy maintained at 70 eV. Reactions of o-Quinones la, lc, Id with YIide 2 in the Presence of TriphenyIph0sphine.-(a) To a stirred solution of phenan- threne-9,lO-quinone la (0.104 g, 0.5 mmol) and triphenyl- phosphine (0.393 g, 1.5 mmol) in dichloromethane (5 cm3) the ylide 2 (0.174 g, 0.5 mmol) was added portionwise during 2 h. The reaction mixture was then stirred for a further 20 h at ambient temperature and then for a further 48 h under reflux and then was cooled to roam temperature to give crystals of 3-(triphenylphosphoranylidene)phenanthro9,l0-bfuran-2-(3H)-one lla (195 mg, 7970, m.p. 25Ck252 "C (decomp.) (from dichloromethane) (lit.,6 m.p. 252 "C).(b)To a stirred solution of 3,5-di-tert-butyl-l,2-benzoquinone lc (0.22 g, 1 mmol) and triphenylphosphine (0.786 g, 3 mmol) in dichloromethane (6 cm3) the ylide 2 (0.348 g, 1 mmol) was added portionwise during 4 h and the reaction mixture was stirred for further 24 h at room temperature and then evaporated to dryness. Chromatography on silica gel with di- chloromethane as the eluent gave three fractions. The first frac- tion gave 5,7-di-tert-butyl-3-ethoxycarbonylmethylenebenzo-bfuran-2(3H)-one 9c (20 mg, 673, m.p. 119-121 "C (from hexane) (lit.,3 m.p. 119-121 "C).The second fraction gave ethyl 6,8-di-tert-butyl-2-oxo-2H-chromene-4-carboxylate8c (41 mg, 1279, m.p. 113-115 "C (from hexane) (lit.,3 m.p. 113-115 "C).The third fraction gave 5,7-di-tert-butyl-3-triphenylphos-phoranylidenebenzobfuran-2(3H)-one llc (0.248 g, 49) m.p. 247-249 "C (from methanol) (lit.,6 m.p. 249 "C). When the same reaction between o-quinone lc (0.44 g, 2 mmol), triphenylphosphine (1.572 g, 6 mmol) and the ylide 2 (0.696 g, 2 mmol) was carried out by adding them at once in dichloromethane (1 7 cm3) under stirring and the reaction mixture was stirred for 48 h at room temperature and then was J. CHEM. soc. PERKIN TRANS. 1 1992 concentrated to a small volume, crystals of compound 1lc were obtained (0.605 g, 60). (c) To a stirred solution of triphenylphosphine (0.262 g, 1 mmol) and ylide 2 (0.348 g, 1 mmol) in dichloromethane (10 cm3) tetrachloro-1,2-benzoquinoneId (0.246 g, 1 mmol) was added portionwise during 2 h and the reaction mixture was then stirred for further 24 h at room temperature.After evaporation of the solvent, the residue was chromatographed on silica gel with dichloromethane as the eluent. Triphenylphosphine (34 mg) was eluted first. The second fraction gave ethyl (3,4,5,6-tetrachloro-2-hydroxypheny1)acetate 12 (0.1 16 g, 3773, m.p. 129-131 "C (dichloromethane-hexane) (lit.,3 m.p. 129-1 31 "C). The third fraction gave tetrachlorocatechol 13 (33 mg, 13), m.p. 193-195 "C (from ethanol) (lit.," m.p. 194-195 "C). The next fraction gave 4,5,6,7-tetrachloro-3-triphenylphosphoranyl-idenebenzobfirran-2(3H)-one1Id (1 1 mg, 2), m.p. 275-277 "C (from dichloromethane) (Found: C, 58.3; H, 3.15.C26H1 ,C1402P requires C, 58.7; H, 2.8); v,,,(Nujol)/cm-' 1710; GH(CDC13)7.34-7.84 (m); m/z 538 (M+ + 8, I(), 536 (M+ + 6,2), 534(M+ + 4,6),532(M+ + 2,23), 530 (M+,8) and 165 (100). When the reaction between triphenylphosphine (0.13 1 g, 0.5 mmol), the quinone Id (0.246 g, 1mmol) and the ylide 2 (0.348 g, 1 mmol) in dichloromethane (5 cm3) was carried out as above, and then hexane was added to the reaction mixture, crystals of compound Ild (24 mg, 4.5) were precipitated. When the quinone Id (62 mg, 0.26 mmol) and triphenylphosphine (0.198 g, 0.75 mmol) was first dissolved in dichloromethane (2 cm3) a spontaneous reaction between them took place, before the addition of the ylide 2, yielding tetrachlorocatechol 13 (44 mg, 69).Wittig Reactions uf Yylides 1la and 1Id with p-Nitrobenzal- dehyde. Preparation of Compounds 14a and 14~~,~,.-(a) To a solution of ylide Ila (0.107 g, 0.216 mmol) in toluene (17 cm3) p-nitrobenzaldehyde (33 mg, 0.218 mmol) was added and the reaction mixture was heated under reflux for 48 h. After the evaporation of the solvent the residue was triturated with dichloromethane to yield red crystals of 3-(4-nitrobenzyl-idene)phenanthro9,1O-bfuran-2(3H)-one 14a (53 mg, 67), m.p. 256-258 "C (from dichloromethane) (Found: C, 74.75; N, 4.1; H, 3.9. C,,Hl,N04 requires C, 75.2; N, 3.8; H, 3.6); v,,,(Nujol)/cm-' 3020, 1765, 1595, 1520 and 1345; d,(CDCl,) 7.48-7.92 (4 H, m), 7.98-8.50 (6 H, m) and 8.64-8.94 (3 H, m); m/z 367 (M+, loo), 339 (42), 294 (30), 293 (33), 292 (23), 265 (38) and 263 (47).(b) A solution of the ylide Ilc (95 mg, 0.19 mmol) and p-nitrobenzaldehyde (29 mg, 0.19 mmol) in dichloromethane (4 cm3) was heated under reflux for 48 h. After evaporation of the solvent, the residue was separated by preparative TLC on silica gel hexane--dichloromethane (1 :l). The faster moving band afforded 5,7-di-tert-butyl-3-(4-nitrobenzylidene)benzobfuran-2(3H)-one 14c, (27 mg, 38), m.p. 162-164 "C (dichloro- methane-hexane) (Found: C, 73.15; N, 3.9; H, 6.35. C23H25N04 requires C, 72.8; N, 3.7; H, 6.6); v,,,(Nujol)/cm-' 1769, 1618, 1590, 1520 and 1340; GH(CDC1,) 1.40 (9 H, s), 1.46 (9 H, s), 7.27 (1 H, s), 7.39 (1 H, s), 7.57 (1 H, s) and 8.17-8.38 (4 H, m); m/z 379 (M+,70), 363 (100) and 335 (16).The next band gave the other isonzer 14C11 (35 mg, 4973, m.p. 183-185 "C (dichloro- methane-hexane) (Found: C, 73.2; N, 3.3; H, 6.9. C2,HZ5NO4 requires C, 72.8; N, 3.7; H, 6.6); v,,,(Nujol)/cm-l 1779, 1630, 1600, 1525 and 1340; GH(CDC13)1.23 (9 H, s), 1.42 (9 H, s), 7.34-7.44 (2 H, m), 7.77 (1 H, s), 7.82 (2 H, d, J7.2) and 8.35 (2 H, d, J 7.2); m/z 379 (M', 56), 363 (100) and 335 (8). The later moving band gave p-nitrobenzaldehyde (3 mg). 3-Metho.u~~piienanthvoC9,1O-b,furun-2( 3H)-one 16.-To a stirred suspension of qiiinone la (0.208 g, 1 mmol) in methanol 287 (10 cm3) heated at reflux was added the ylide 2 (0.418 g, 1.2 mmol) portionwise over 4 h and the reaction mixture was then refluxed for a further 20 h under stirring.The hot reaction mixture was then filtrated to give crystals of compound 16 (81 mg, 31), m.p. 22amp;222 "C (decomp.) (from methanol) (Found: C, 77.1; H, 4.3. C17H12O3 requires C, 77.25; H, 4.6); vm,,(Nujol)/cm-' 1815; S,(CDC13) 3.31 (3 H, s), 7.34 (1 H, s, partially overlapped by CHCI,), 7.56-7.90 (5 H, m), 8.27-8.44 (1 H, m) and 8.57-8.74 (2 H, m); m/z 264 (M+,4473, 236 (56), 221 (loo), 220 (81) and 205 (19). The filtrate was evaporated to dryness. Chromatography on silica gel with dichloromethane- hexane (3: 1) as eluent gave first an additional amount of compound 16 (35 mg, 13), total yield 44. The next fraction gave compound 8a (0.1 12 g, 35). Ethyl (33- Di-tert-btityl-2-hydro.xyphen~~l)erho.uq~acetate17.-To a solution of quinone lc(0.44 g,2 mmol) in ethanol (1 7 cm3), heated at reflux, was added the ylide 2 (0.696 g,2 mmol) over 5 h and the reaction mixture was then refluxed for a further 24 h.The solvent was evaporated and the oily residue was triturated with ether to yield crystals of compound llc (45 mg, 4). The filtrate was evaporated to dryness. Chromatography of the residue on silica gel with hexane-dichloromethane (3: 141 :1) as eluent gave three fractions. The first fraction gave compound 9c (24 mg, 4). The second fraction gave compound 17 (35 mg,573, m.p. 125-127 "C (from hexane) (Found: C, 71.15; H, 9.9. C20H3204 requires C, 71.4; H, 9.67;); v,,,(Nujol)/cm-' 3400 and 1735; amp;(CDC13) 1.25 (3 H, t, J6.4), 1.38 (3 H, t, J7.2), 3.60 (2H,q7J6.4),4.l9(2H,q,J7.2),5.35(1H7s),7.27(1H,s)and 8.68 (1 H, s); nz/z 336 (M+, 18), 335 (66), 318 (16), 307 (35), 305 (43), 291 (17), 277 (44), 263 (38), 234 (44), 233 (99), 232 (64), 230 (60), 218 (35) and 217 (100).The third fraction afforded compound 8c (0.285 g,43). Reaction of Quinone la with Ylide 2 in Ethyl Acetate.-A solution of quinone la (0.104 g,0.5 mmol) and ylide 2 (0.348 g, 1 mmol) in ethyl acetate (5 cm3) was stirred at room temperature. The reaction was monitored by TLC examination of the mixture. After 2 h all the starting quinone was consumed. The solvent was evaporated and the residue was chromatographed on silica gel, with hexane-dichloromethane (1 :1) as eluent to give ethyl 2-oxo-2H-dibenzof,hchromene-4-carboxylate8a (0.11 g,69",), m.p.158-1 59 "C (from ethanol) (lit.,' m.p. 158 "C). Reactions of Quinones lad with Ylide 2 in Acetic Anhydride. Preparation of Compounds 18a, 18b, 18d, 19b, 19d and 24.-(a) A solution of quinone la (0.4 16 g, 2 mmol) and ylide 2 (1.392 g, 4 mmol) in acetic anhydride (5 cm3) was heated at ca 60 "C for 8 h. The reaction mixture was then poured into water (30 cm3) and extracted with ether (4 x 40 cm3). The extract was dried over Na2S04 and evaporated to dryness. Chromatography on silica gel with hexane-ethyl acetate (9.9:0.1-+9 : 1) as eluent gave three fractions. The first fraction gave ethj'l 2-methyl- phenanthroC9, lO-b, furan-3-carbo.~ylate 24 (44 mg, 773, m.p. 109-1 10 "C (dichloromethane-hexane) (Found: C, 78.8; H, 5.4.C20H160, requires C, 78.9; H, 5.3); v,,,(Nujol)/cm-' 1705 and 1615;dH(CDC13)1.47 (3 H, t, J 8.0), 2.80 (3 H, s), 4.50 (2 H, d, J8.0), 7.43-7.79 (4 H, m), 8.18-8.37 (1 H, m), 8.57-8.79 (2 H, m) and 9.04-9.26 (1 H, m); mi2 304 (M+,1000/,), 278 (16), 277 (30), 276 (24), 275 (51), 231 (16), 230 (19), 202 (59) and 152 (27). The second fraction afforded compound 8a (0.16 g, 25). The third fraction gave colourless crystals of diethjd (1O-aceto.xy-9-phenanthryl).funmrate 18a (0.503 g, 620/,), m.p. 70-72 "C (from ethanol) (Found: C, 70.8; H, 5.6. C24H22O6 requires C, 70.9; H, 5.5); v,,,(Nujol)/crn-' 1760, 1725 and 1720; SH(CDC13)0.63 (3 H, t, J8.0), 1.10(3 H, t, J9.0), 2.35 (3 H, s), 3.81 (2 H, q, J9.0), 4.19 (2 H, q, J KO), 7.26-7.92 (6 H, m) and 8.42-8.79 (2 H, m); nz/z 407 (15), 406 (M', 24), 364 (loo), 318 (64) and 290 (53).When the same reaction between compounds la and 2 in acetic anhydride was carried out at room temperature compounds 8a (5373 and 18a (28) were again obtained. (b) The reaction between quinone lb (0.158 g, 1 mmol) and ylide 2 (0.696 g, 2 mmol) in acetic anhydride (2 cm3) at 60 "C for 10 h was carried out and the reaction mixture was worked up, as described above for quinone la, to give, from the first fraction, compound 8b (23 mg, 973, m.p. 147-148 "C (chloroform- hexane) (lit.,' m.p. 148 "C). The next fraction gave dietlijvl (1-aceto.u~-2-napl?th~l)maleate19b (83 mg, 23), m.p. 52-54 "C (from ethanol) (Found: C, 67.3; H, 5.55.C,,H2,06 requires C, 67.4; H, 5.7); v,,,(Nujol)/cm-' 1760 and 1720; dH(CDC13) 1.29 (6H,t, J7.2),2.42(3H,s),4.25(2H7q,J7.2),4.34(2H7q,J7.2), 6.30 (1 H, s) and 7.34-7.91 (6 H, m); m/z 356 (M+, 7873, 312 (loo), 266 (54) and 240 (42). (c) The reaction between the quinone Ic (0.44 g, 2 mmol) and the ylide 2 (1.392 g, 4 mmol) in acetic anhydride (5 cm3) for 24 h, at room temperature, was carried out and the reaction mixture was worked up as above to give first compound 9c (0.48 g, 737'J. The next fraction afforded compound 8c (26 mg, 4). The third fraction gave ylide 25 (0.302 g, 19), m.p. 171-173 "C (dichloromethane-hexane) (lit.,' lb m.p. 172-1 74 "C). (d) The reaction of quinone Id (0.492 g, 2 mmol) with ylide 2 (1.392 g, 4 mmol) in acetic anhydride at 60 "C for 30 min was carried out and the reaction mixture was worked up as described for quinone la.The following fractions were eluted. The fraction eluted first gave 18d (0.29 g, 3373, m.p. 61-63 "C (from hexane) (lit.,3 m.p. 61-63 "C). The next fraction afforded diethyl(2-aceto.x~~-3,4,5,6-tetrachlorophenyl)maleute19d (0.21 g, 24), oil (Found: C, 43.0; H, 3.1. C16H14c1406 requires C, 43.3; H, 3.2); v,,,(liquid film)/cm-' 1787, 1735, 1725, 1640 and 1560; G,(CDCI,) 1.23 (3 H, t, J 7.0), 1.32 (3 H, t, J 7.4), 2.31 (3 H, s), 4.21 (2 H, q, J 7.0), 4.28 (2 H, q, J 7.4) and 6.21 (1 H, s); m/z 448 (M+ + 6, 0.8), 446 (M+ + 4, 4), 444 (M+ + 2, 9) and 442 (M +,6). The next fraction gave triphenylphosphine oxide (0.46 g, 83) and the following fraction afforded ylide 25 (0.425 g, 27).Conversion of18a into 8a.-A solution of compound 18a (67 mg, 0.165 mmol) and concentrated hydrochloric acid (0.5 cm3) in ethanol (3 cm3) was heated at reflux for 6 h. Then the reaction mixture was cooled to room temperature to give crystals of compound 8a (52 mg, 99"/1). Conuersion qf 18b into 8b and 9b.-A solution of compound 18b (0.1 16 g, 0.326 mmol) and concentrated hydrochloric acid (0.5cm3) in ethanol (3 cm3) was left to stand for 64 h at room temperature. The solvent evaporated to dryness. Separation by preparative TLC on silica gel hexane-dichloromethane (1 :l) afforded from the faster moving band compound 9b (6 mg, 773, m.p. 187-189 "C (chloroform-hexane) (lit.,3 m.p.187-189 "C). The next band gave compound 8b (51 mg, 52). The slower moving band gave unchanged compound 18b (39 mg, 34). Conuersion qf 19b into 8b and 9b.---A solution of compound 19b (82 mg, 0.23 mmol) and concentrated hydrochloric acid (0.5 cm3) in ethanol (3 cm3) was stirred for 9 d at room temperature. The solvent evaporated to dryness. Chromatography on silica gel with dichloromethane-hexane (1 : 1) gave three fractions. The first fraction afforded compounds 9b (10 mg, 1604)). The second fraction gave compound 8b (25 mg, 41xJ. The third fraction gave unreacted compound 19b (36 mg, 40). Conversion of'18d into 6d.-A solution of compound 18d (20 mg, 0.045 mmol) and concentrated hydrochloric acid (0.3 cm3) in ethanol (2 cm3) was heated at reflux for 24 h.The solvent evaporated to dryness to give diethyl (2,3,4,5-tetrachloro-6- J. CHEM. SOC. PERKIN TRANS. I 1992 hydroxypheny1)fumarate 6d (18 mg, 10O0.), m.p. 76-78 C (ethyl acetate- hexane) (lit.,3 m.p. 76 -78 -C). Ethjil (4- Etlio.bsol;-?~c.urhon!~l-2H -phennnthro9, IO-b pj3rcrn-2-j9I-idene)ucetate 26.-A solution of compound 8a (0.3 18 g, 1 mmol) and ylide 2 (0.348 g, 1 mmol) in toluene (5 cm3) was heated at reflux for 3 d. The solvent evaporated to dryness in a rotary evaporator. Chromatography on silica gel with ethyl acetate- hexane ( 1 :2) gave compound 26 (0.186 g,48), m.p. 140-1 4 1 "C (from ethanol) (Found: C, 74.1; H, 5.3. C24H2005 requires C, 74.2; H, 5.2); v,,,(Nujol)/cm-' 1735, 1730, 1680, 1630 and 1600; d~(cDC13) 1.25 (3 H, t, J9.0), 1.49 (3 H, t, J9.0), 4.28 (2 H, q, J9.0),4.60(2H,q, J9.0),5.56(1 H7s),7.40-7.93(6H,m)and 8.16-8.64 (3 H, m); rn/z 389 (25), 388 (M', 92), 343 (19), 316 (89), 288 (18) and 214 (100).The next fraction afforded unreacted compound 8a (99 mg, 3 1). Ethjd (3,4- Dihydro-4-e tho.u~~curbonj~l-2H -pilenunthro 9,10- bp?~ran-2-~~1)acetate28.-(u) A solution of compound 26 (78 mg, 0.2 mmol) and triphenylphosphine (0.131 g, 0.5 mmol) in toluene (5 cm3) was heated at reflux for 48 h. The solvent was evaporated to dryness. Chromatography on silica gel with hexane-dichloromethane (I :1) as eluent gave compound 28 (14 mg, 18), m.p. 70-72 "C (from ethanol) (Found: C, 73.3; H, 6.3. C24H240, requires C, 73.45; H, 6.2); v,,,(Nujol)/cm-' 1740, 1730 and 1625; dH(CDC1,) 1.02-1.87 (6 H, m), 2.20-2.84 (4 H, m), 3.5W.15 (6 H, m), 7.05-7.82 (5 H, m) and 8.40-8.72 (3 H, m); m/z 392 (M', 56), 320 (48) and 248 (100).(b) To a stirred melted mixture of quinone la (0.208 g, 1 mmol) and coumarin 29 (0.73 g, 5 mmol), heated at cu. 70 'C, ylide 2 (0.522 g, 1.5 mmol) was added in portions during 2 h. The reaction mixture was separated by column chromatography on silica gel. Elution with hexane-ethyl acetate (9: 1) gave three fractions. The first fraction gave compound 28 (47 mg, 12:9. The second fraction gave coumarin 29 (0.701 g, 96) and the third fraction gave compound 8a (0.149 g, 47). Ethjd (2H-Ben=obp~~ran-2-~~lidene)crcetate30.-A mixture of coumarin 29 (0.292 g, 2 mmol) and ylide 2 (0.696 g, 2 mmol) was heated in an oil bath at CCI.115 "C for 48 h, and then chromatographed on silica gel with hexane+thyl acetate (2: 1) as eluent to give compound 30 (0.151 g, 3573, m.p. 75-76 'C (from ethanol) (Found: C, 72.3; H, 5.6. C13H1203 requires C, 72.2; H, 5.6"/,); vmax(Nujol)/cm-l 1695sh, 1680 and 1600; h~(cDC13) 1.27 (3 H, t, J9.0), 4.16 (2 H, 9, J9.0), 5.38 (1 H, s), 6.88-7.36 (5 H, m) and 7.83 (1 H, d, J 14); m/z 216 (M', 40deg;/;,), 171 (87) and 114 (100). References I H. J. Bestmann and H. J. Lang, Tctrdirciron Lett., 1969, 2101. 2 F. M. Soliman, K. M. Khalil and G. Abdelnaim, Pho.sp1ioru.sSulfiri. Rcltrt. Eh., 1988,35, 41. 3 D. N. Nicolaides, S. G. Adamopoulos, D. A. Lefkaditis and K.E. Litinas. J. Cheni. Soc., Pdiitl Trm.7. I, 1990,2 127. 4 D. N. Nicolaides, D. A. Lefkaditis, P. S. Lianis and K. E. Litinas. J. Clieni.Sot., Prrkiri 7'ruii.v. I, 1989, 2329. 5 J. Brugidou and H. Christol, Bull. Soc. Chirii. Fr., 1966, 2688; R. R. Schmidt, Tetr(hcdroti Lett., 1969, 5279; T. Inoue, S. Inoue and K. Sato, Choji. L~tt.,1989, 653. 6 R. W. Saalfrank, E. Ackermann, H. Winkler. W. Paul and R. Bohme. Clicwi.Bcr., 1980, 113, 2950. 7 J. W. Kelly, P. L. Robinson and S. A. Evans. Jr., J. Org. c'licrii., 1986, 51,4473. 8 ((1) K. Sunitha and K. K. Balasubramanian, Tc~trrrlic~tlrwii.1987. 43. 3269; (h) L. T. Byrne. L. M. Engelhardt, F. R. Hewgill and B. W. Skelton, J. C'licvii. Soc.. Pcrkiri Tr~ui.bsol;.I. 1989. 133. 9 V. 0.Kozminykh, E. N. Kozminykh and Yu. S. Andreichikov, Kliiiii. GctcrwtsiX.1. Soctiiii, 1989, 8, 1034. 10 D. A. Bolon, J. Org. Clicwi., 1970, 35. 3666; B. A. M. Oude-Alink, J. CHEM. SOC. PERKIN TRANS. 1 1992 A. W. K. Chan and C. D. Gutsche, J. Org. Chem., 1973. 38, 1993; L. Jurd and R. Y. Wong, Aust. J. Chem., 1981,34, 1645. 11 (a)A. W. Johnson, YIid Chemistry, ed. A. T. Blomquist, Academic Press, London 1966, pp. 102-106; (6) P. A. Chopard, R.J. G. Searle and F. H. Devitt, J. Org. Chem., 1965.30, 1015. 12 W. G. Dauben and D. J. Hart, Tetrahedron Left., 1975, 4353; W. Ding, P. Zhang and W. Cao, Tetrahedron Lett., 1987,28,81. 13 M. von Strandtmann, M. P. Cohen, C. Puchalski and J. Shave1 Jr., J. Org. Chem., 1968,33,4306. 14 I. Gosney and A. G. Rowley, Organophosphorus Reagents in Orgunic Sj*nfhesis, ed. J. I. Cadogan, Academic Press, London 1979, p. 22. 15 M. S. Chauhan, F. M. Dean, D. Matkin and M. L. Robinson, J. Chem. Soc., Perkin Trans. 1, 1973, 120. 16 C. A. Henrick, E. Bohme, J. A. Edwards and J. H. Fzied, J. Am. Chem. Soc., 1968, 90, 5926; H. Kise, Y. Ardse, S. Shiraishi, M. Seno and T. Asahara, J. Chem. SOC.,Chem. Commun., 1976, 299; J. Le Roux and M. Le Corre, J. Chem. SOC.,Chem. Commun., 1989, 1464. I7 E. Hedaya and S. Theodoropoulos, Tetrahedron, 1968,24,2241. 18 T. Zincke and F. Kuster, Chem. Ber., 1888,21,2719. Paper 1 /03700E Received 19th July 1991 Accepted 2nd October 199 1