1976 639Organic Synthesis using Diphenylphosphinoyl as a Migrating FunctionalGroup : Diene SynthesisBy Alan H. Davidson and Stuart Warren,' University Chemical Laboratory, Lensfield Road, Cambridge CB2 1 EWAllyldiphenytphosphine oxides can be made from a carbonyl compound, an alkyl halide, and a diphenylphosphinoylreagent by two routes, one involving migration of the diphenylphosphinoyl group. Lithium derivatives of theseallylphosphine oxides add stereoselectively to aldehydes and the products undergo elimination of diphenyl-phosphinic acid stereospecifically to give single geometrical isomers of substituted dienes.DIENES (3) can be synthesised by the Wittig reactionbetween allylphosphonium ylides (2) and carbonylcompounds.2 The two most serious problems to befaced along this route are that the ylide (2) niay reactthrough either the a- or the y-carbon atom, and thatall four geometrical isomers of the diene may well bef ~ r m e d .~4. + n ,'R (2)We report that the Horner5 variant of the Wittigreaction can be used to make single geometrical isomersof substituted dienes (6). The key intermediates are theallylphosphine oxides (4). In many cases these reactwith butyl-lithium and a carbonyl compound regio-specifically and stereoselectively to give the crystallineintermediates (5), which can be separated into diastereo-isomers by chromatography and crystallisation. Elimin-ation with a sodium base (e.g. NaH) then gives the dienes(6) stereospecifically, the other product being the easilyextracted diphen ylphosphinic acid.6The allyldiphenylphosphine oxides (4) may be madeby a number of methods in which the complete allylfragment is added to a suitable electrophilic or nucleo-philic phosphorus reagent.We have found that thesecompounds can be made by the dehydration of tertiaryalcohols [ e g . (7)] in acid. Brief treatment with tri-fluoroacetic acid gives the allyl compound (8); moreprolonged treatment gives the vinyl compound (9). If1 Preliminary communication, A. H. Davidson and S. Warren,J.C.S. Chem. Comm., 1975, 148.H. von Brachel and, U. Bahr, in Houben-Weyl, ' Methodender Organischen Chemie, Thieme, Stuttgart, 1970, vol 5/lc, pp.3 E. J . Grey and B. W. Erikson, J . Org. Chem., 1974,39,821;E. Vedejs, J. P. Bershas, and P.L. Fuchs, ibid., 1973, 38, 3625;these papers refer to extensive earlier work.4 The thinking behind our work on synthesis is explained inA. H. Davidson, P. K. G. Hodgson, D. Howells, and S. Warren,Chem. and Ind., 1975, 455.L. Horner, H. Hoffmann, and H. G. Wippel, Chem. Ber.,1968, 91, 61 ; L. Horner, H. Hoffmann, H. G. Wippel, and G.Klahre, ibid., 1959, 92, 2499; L. Horner, H. Hoffmann, W.Klink, H. Ertel, and V. G. Toscano, ibid., 1962, 95, 581; L.Horner, W. Klink, and H. Hoffmann, zbid., 1963, 96, 3133; L.Horner, Fovtschr. Chem. Fovsch., 1966, 7, 1.690-601.trifluoroacetic acid is used, the reaction is convenientlyfollowed by n.m.r. Presumably the allyl compound isthe kinetic, and the vinyl compound (9) the thermo-dynamic product.Where the substitution pattern is reversed so that thealcohol is secondary and the diphenylphosphinoyl groupon a quaternary carbon [e.g.(lo)] dehydration occurswith rearrartgement to give the same allylphosphine oxide(8). We have previously reported lo that this reactionoccurs on solvolysis of derivatives (tosylate or mesylate)of the alcohol (10) but we have now found that it alsooccurs simply on heating the alcohol itself in benzenesolution under reff ux with toluene-P-sulphonic acid.Presumably the tertiary cation (11) is an intermediatein both reactions (7) (8) and (10) (8).10)Both alcohols (7) and (10) may be made by the firststage of the Wittig-Horner rea~tion,~ that is by treat-ment of a phosphine oxide (12) with butyl-lithium and acarbonyl compound. Primary alkylphosphine oxides(12 ; R2 = H) are most economically made by quaternis-ation of triphenylphosphine and hydrolysis of thephosphonium salt l1 (13), the other product being benzene.A.J. Bridges and G. H. Whitham, J.C.S. Chem. Cornm., 1974,142.7 H. R. Hays and D. J. Peterson in ' Organic PhosphorusCompounds,' eds. G. M. Kosolapoff and L. Maier, Wiley, NewYork. 1972, vol. 3, pp. 341-500.8 M. P. Savage and S. Trippett, J . Chm. SOC. (C), 1966, 1842;1967,1998; 1968,591.9 I. M. Downie and G. Morris, J . Chern. Soc., 1965, 5771.l o D. Howells and S. Warren, J.C.S. Perkin 11, 1973, 1472,1645.11 L. Horner, H. Hoffmann, and H. G. y p p e l , Chem. Bey.,1958, 91, 64; K.,Sasse in Houben-Weyl, Methoden der Or-ganischen Chemie, Thieme, Stuttgart, 1963, vol.1211, pp. 144-150640 J.C.S. Perkin I:So, starting with either cyclohexyl or ethyl-diphenyl-phosphine oxide (Scheme 2) we have synthesised theallylphosphine oxide (21) via the tertiary alcohol (19) or,This reaction can also be used for secondary halides butthe quaternisation is rather slow, and they may alterna-tively be converted into Grignard reagents andcombined l2 with the acid chloride (15) made by recyclingthe ' waste product ' of the Wittig-Horner reaction,diphenylphosphinic acid (14).UR'CH Br + I1Ph3P Ph,P-CH2R1 Ph,PCH2R1 + PhH"2O(13)These two routes to allylphosphine oxides (16)(Scheme 1) involve the same disconnection (17a or b)and, during retrosynthetic analysis,13 the choice betweenthem would depend on the availablity of the fragmentsas alkyl halides or as carbonyl compounds, since oneelectrophile of each type is used.Whether rearrange-ment is involved or not, the diphenylphosphinoyl groupis used to link together a series of electrophilic moleculesinto the final diene structure (18) as it is derived from twocarbonyl compounds and an alkyl halide. This requiresumpolung l4 which arises because the phosphorus atom,0( b 1 withF % * y rec rrangementK? (is1 Q( a ) withoatrearrangementCHR*R0Ph,; k CHzRZR OHJJ VO R' 0 0 C H ~ R ~Ph2kJ + +cH2R2 Phzk!--( +R'CHOR R'20 II ' CH,RPh3P t R'CH2Hal Ph2P-CL + Hal -(RSCHEME 1 Retrosynthetic analysis of allylphosphine oxidesynthesiswhether in the initial P-C bond-forming reaction orduring the rearrangement, becomes bonded to anelectrophilic atom, but can then stabilise a negativecharge or lithium derivative on that atom.l2 D.C. Morrison. 1. Amer. CAem. Soc., 1950, 72, 4820.13 I. Fleming, ' Sefected Organic Syntheses,' Wiley, London,1973, p. 3; see also E. J. Corey, R. I). Cramer, and W. J . Howe,T. Amer. Chem. SOC.. 1972. 94. 440.RLCHO t R3CH2Hal + R2CO-CH,dwithout rearrangementR2xcHR: ~ ;321 C H R ~ 8R3 CHR POPh2 9with rearrangement (18)R'CHO + R3CH0 t R'CH Hal. C 3 R 'with rearrangement of the diphenylphosphinoyl group,via the secondary alcohol (20). In the dehydration of( b l with rearrangement : a ) without rearrangementn vP h 2 ! ' i t 0 0 '0 4- MeCHOPh, PHPh2P 4 2HR a"HO+ H'R(22b)H I?( 2 3 f ) ( 2 3 1 )SCHEME 2 Synthesis of dienesthe tertiary alcohol (19) in trifluoroacetic acid, the allyl-phosphine oxide (21) is not transformed into the vinyl-(2L)phosphine oxide (24) presumably because the weak $,-d, conjugation between C=C and P=O is outweighed byl4 D.Seebach, Chem. andInd., 1974, 687. the disadvantage of an exocyclic double bond1976 641Treatment of the allylphosphine oxide (21) with butyl-lithium and acetaldehyde or benzaldehyde gave pairs ofdiastereoisomeric alcohols (22) in ratios [(a) : (b)] of 2 : 1{for R = Me) or 1 : 3 (for R = Ph). In neither case wasthere any significant y-addition. However, y-additionto this allylphosphine oxide gives an unfavourableexocyclic double bond.The highly crystalline alcoholswere separated and converted into the dienes (23) bysodium hydride in tetrahydrofuran or dimethylform-amide.6 All diastereoisomers of the alcohols (22) anddienes (23) are easily distinguished by their n.m.r.spectra.Addition of maleic anhydride to the dienes (23) gavethe Diels-Alder adducts (26) whose n.m.r. spectraallowed us to make an unambiguous assignment ofL I6 7T, ..., i i i l (26a; R = P h )5 7T7 T 6( i v ) (26b;R = PhlII I6.11 6.69TN.m.r. spectra of maleic anhydride adducts (26) at 100 MHz[except (iv) which is at 80 MHz] by Fourier transformconfiguration to series (a) and (b) (Scheme 3). Assumingerndo-addition, the only chiral centre in question is thatbearing Hd in (26).The only protons whose n.m.r.signals emerge from the methylene envelope are Hb andHc and, for R = Ph, Hd. These signals are shown in theFigure. In series (a) protons Hb and Hc give a sym-metrical signal which, though not first-order, shows thatall the coupling constants Jab, Jbc, and Jcd are about thesame (ca. 9 Hz). This is confirmed in the phenyl com-pound (26a; R = Ph) by the doublet for Hd ( J 6 Hz).For (26b; R = Me) Hb and Hc give a first-order patternof a triplet ( J 9 Hz) and a double doublet (J 9 and 2 Hz),suggesting that Jab = Jbc = 9 Hz, and Jcd = 2 Hz.For (26b; R = Ph) this signal is not first order but thesignal for Hd is a broad singlet (Jca 2 Hz).Is - CIS 1 R s -trans(22a) [ 2 3 E )R=Me; 0 - 4minor product;Iower R,0% E i HH WR j R = Ph;~maw.271*5nm(C16 902);major product; I26a) fast Diels- Alder reactionlower R,H(22 b )R = M e ;major product;higher RFR=Ph;minm product ihigher RFAmaxe 2 6 0 ( ~ 3 767) and 266nrni3 729:;slow Dieis-Alder react ionSCHEME 3 Configurations of alcohols (22), dienes (23), andDiels-Alder adducts (26)Models suggest that the conformation of the cyclo-hexene ring is boat-like with angles between the cis-substituents [e.g.Ha, Hb, HC, and Hd in series (a)] of ca.45", and angles between the trans-substituents [q. Hcand Ha in series (b)] of ca. 75". So we assign the sym-metrical signals with larger coupling to the all-cis-seriesand the smaller coupling to the only tram-protons, Hcand Hd in series (b).Since both the syz-elimination ofdiphenylphosphinic acid and the Diels-Alder reaction arestereospecific we can write the structures of alcohols (22)and dienes (23) as in Scheme 3. Additional evidence onthe structure of the dienes (23; R = Ph) comes from thelonger wavelength absorption of the E-isomer and th642 J.C.S. Perkin Ireluctance with which the Z-isomer undergoes the Diels-Alder reaction because of its unfavourable s-cis-conform-ation. The stereoselectivity of the Horner reaction isdifferent in that (22a) is favoured by 2 : 1 for R = Me but(22b) is favoured by 3 : 1 for R = Ph.EXPERIMENTALGeneral spectroscopic and chromatographic procedureshave been described previ0us1y.l~ Petrol refers to lightpetroleum (b.p.60-80'). RF Values are quoted fordevelopment in ethyl acetate.Cyclohexyldiphenylphosphine Oxide (method of ref. 12) .-Diphenylphosphinic acid l6 (2 g) was heated under reflux intoluene with thionyl chloride (10 ml) for 1.5 h. The excessthionyl chloride was removed by evaporating most of thetoluene under reduced pressure. The residue was dilutedwith dry benzene (50 ml) and added dropwise over 1.5 h tocyclohexylmagnesium bromide [from cyclohexyl bromide(15 ml) and magnesium (2 g)] in ether (100 ml). Thesolution was heated under reflux for 2 h, then cooled to 0 "C,and ice (25 g) and hydrochloric acid (10%; 50 ml) wereadded. The aqueous layer was extracted with ether(3 x 50 ml) and the combined ethereal layers were dried(MgSO,) and evaporated; the product was collected andrecrystallised from ethyl acetate to give the phosphineoxide (1.9 g, 65%), m.p.164-166" (lit.,I7 165"), R p 0.25,vm, 1440 (PPh) and 1 185 cm-l ( P O ) , T (CDC1,) 2.0-2.7(10 H, m, Ph,PO), 6.6-7.0 (1 H, m, PCH), and 8.0-8.8(10 H, m, CH, envelope), na/e 284 (40%, M f ) and 201 (100,Ph,PO) .(20) .-C yclo-hexyldiphenylphosphine oxide (350 mg) in dry ether (50 ml)was stirred at 0 "C under nitrogen with n-butyl-lithium(1 ml; 1 . 5 ~ in hexane) for 0.5 h. The red solution wascooled to -78 "C and acetaldehyde (40 mg) in ether (4 ml)added over 5 min. The solution was allowed to warm up to0 "C, the treatment with butyl-lithium and acetaldehydewas repeated, and water (50 ml) was added. The aqueouslayer was extracted with chloroform (3 x 25 ml) and thecombined organic layers were dried (MgSO,) and evaporatedunder reduced pressure.The residue was recrystallisedfrom ethyl acetate-di-isopropyl ether to give the alcohol(300 mg, 75%), m.p. 180-184", l i p 0.33, v,, 3 350 (OH),1 440 (PPh), and 1 170 cm-l ( P O ) , T (CDC1,) 1.8-2.8 (10 H,m, Ph,PO), 5.6 (1 H, dq, JPH 26, JHH 6Hz, PC-CHMe), 5.6(1 H, s, OH), 7.3-8.7 (10 H, m, CH, envelope), and 8.85(3 H, d, JHH 6 Hz, CHMe), m/e 328 (8%, M'), 284 (90, M -MeCHO), and 201 (100, Ph,PO) (Found: C, 73.2; H, 7.6;I?, 9.0. C,,H,,O,P requires C, 73.3; H, 7.6; P, 9.4%).Preparation of Tosylates: 1- (l-Diphenylphosphinoylcyclo-hexyE)ethyl Toluene-p-su1phonate.-This procedure is typical.The alcohol (20) (400 mg) in dry tetrahydrofuran (50 ml) wasstirred with n-butyl-lithium (1 ml; 1 .5 ~ in hexane) at 0 "Cunder nitrogen for 20 min. Toluene-p-sulphonyl chloride(400 mg) in dry tetrahydrofuran (10 ml) was added slowlyand the solution stirred a t room temperature for 0.5 h.Saturated sodium hydrogen carbonate solution (50 ml) wasadded and the organic layer was separated, washed withdilute hydrochloric acid (50 ml) and brine (50 ml), and dried(MgSO,). Removal of solvent under reduced pressure andl5 P. K. G. Hodgson and S. Warren, J.C.S. Perkin I I , 1975,372.l6 G. M. Kosolapoff and R. F. Struck, J . CAem. Soc., 1959,3960.1- ( 1 -Dip henylp hosp hinoy lcylohexyl) ethanolrecrystallisation of the residue from ethyl acetate gave thetosylate (400 mg, 55%), m.p.117-120", Rpl 0.38, v-1440 (PPh), 1370, 1180 (SO), and 1185 cm-l (P=O), T(CDC1,) 1.9-2.9 (14 H, m, Ar), 4.P-4.8 (1 H, dq, JHH 6 Hz,PCCHMe), 7.6 (3 H, s, MeAr), 7.7-8.7 (10 H, m, CH,envelope), and 8.5 (3 H, d, J H H 6 Hz, CHMe).Solvolysis of Tusylates: 1-( 1-Diphenylphosphi~oylethyl)-cyclohexene (2 1) .-(a) By trifluoroacetolysis. The abovetosylate (180 mg) in trifluoroacetic acid (10 ml) containinganhydrous sodium trifluoroacetate (40 mg) was kept a t70 "C for 8 h and 25 "C for 14 h. The solution was pouredinto water (50 ml) and extracted with ether (3 x 50 ml),The combined ether layers were washed with sodiumhydrogen carbonate solution (2 x 50 ml) and water (50 ml),dried (MgSO,) , and evaporated. Recrystallisation of theresidue from ethyl acetate-di-isopropyl ether gave theolefin (21) (100 mg, 85y0), m.p.145-147", R, 0.3, v,, 1 440(PPh) and 1 180 cm-l ( P O ) , T (CDCl,) 2.0-2.8 (10 H, m,Ph,PO), 4.5 (1 H, S, CH=C), 7.1 (1 H, quint, J ~ H = J E H =7 Hz, P-CHMe), 7.8-8.8 (8 H, m, CH, envelope), and 8.7(3 H, dd, JPH 16, JHH 7 Hz, PCHMe), m/e 310 (35%, M+),228 (100, Ph,PO*CH:CH,), and 201 (50, Ph,PO) (Found:C, 77.5; H, 7.65; P, 10.2. C,oH,,OP requires C, 77.4; H,(b) By acetolysis. The above tosylate (100 mg) wasstirred in acetic acid (dried by distillation from acetic acid,acetic anhydride, and chromium trioxide; l8 10 ml) andanhydrous sodium acetate (100 mg) for 24 h at 70 "C. Thesolution was poured into water and worked up in the sameway as the trifluoroacetolysis product to give the same olefinDirect Conversion of the Alcohol (20) into the Olefin (21).-The alcohol (20) (50 mg) was heated under reflux in drybenzene (25 ml) and toluene-p-sulphonic acid (50 mg) in aDean-Stark apparatus for 24 h.The solution was pouredinto saturated aqueous sodium hydrogen carbonate (50 ml)and extracted with chloroform (3 x 25 ml), the extractswere washed with water (25 ml) and dried (MgSO,).Evaporation under reduced pressure and recrystallisationfrom ethyl acetate gave the olefin (21) (38 mg, 80%).1-( 1-Diphenylphosphinoylethyl) cyclohaxanol (1 9)-Di-phenylethylphosphine oxide (6 g) in dry ether (200 ml) undernitrogen was stirred with n-butyl-lithium (16 ml; 1 . 7 ~ inhexane) for 0.5 h and cooled to -78 "C.Cyclohexanone(3 g) in dry ether (50 ml) was added, the solution wasallowed to warm up to room temperature, and water (200ml) was added. The crystalline alcohol (7 g, 80%) had m.p.185-187" (from ethyl acetate-petrol), RF 0.5, vmx 3 600(OH), 1440 (PPh), and 1 170 cm-l ( P O ) , T (CDC1,) 2.0-2.8 (10 H, m, Ph,PO), 5.3 (1 H, s, OH), 7.4br (1 H, quint,JPH = J=H = 8 Hz, PCHMe) , 8.0-9.0 (10 H, m, methyleneenvelope), and 8.85 (3 H, dd, Jp= 16, JHH 8 Hz, PCHMe),m/e 328 (20%, M+), 310 (16, M - H,O), 285 (42), 230 (62,Ph,POEt), 202 (100, Ph,POH), and 201 (80, Ph,PO) (Found:C, 73.3; H, 7.5; P, 9.7. C20H,,0,P requires C, 73.2; H,7.6; P, 9.45%).1-( l-DiphePzylphosphinoy1ethyl)cyclohexene (21) from theTertiary Alcohol (19) .-The alcohol (1 9) (5 g) was stirred intrifluoroacetic acid (25 ml) at 70" for 25 min and thesolution poured into water (100 ml), and extracted withchloroform (3 x 50 ml).The extracts were washed with7.4; I?, lo.oyo).(21) (63 mg, 96%).l7 E. Muller and H. G. Padeken, Chem. Ber., 1967, 100, 521;L. Horner H. Hoffmann, and H. G. Wippel, ibid., 1958, 91, 61.D. D Pemn, W. L. F. Armarego, and R. H. Perrin. Puri-fication of Laboratory Chemicals,' Pergamon, London, 19661976 643aqueous sodium hydrogen carbonate (3 x 50 ml), dried(MgSO,) , and evaporated. The solid residue was recrystal-lised from ethyl acetate to give the olefin (21) (4.3 g, 86%,characterised above).3- (Cyclohex- 1-enyl) -3-diphenylpkosphinoylbutan-2-ol (22;R = Me).-The olefin (21) (5 g) in dry ether (200 ml) wasstirred with n-butyl-lithium (12 ml; 1 .5 ~ in hexane) undernitrogen for 0.5 h. The solution was cooled to -78 "C anda solution of acetaldehyde in ether saturated with anhydrouslithium bromide was added until the red colour was dis-charged.Further additions of n-butyl-lithium at room temperatureand acetaldehyde at -78" were made until the addition ofn-butyl-lithium no longer produced a red colour. Thesolution was allowed t o reach room temperature and water(200 nil) added; the aqueous layer was extracted withchloroform (3 x 50 nil) and the combined aqueous layerswere dried (MgSO,) and evaporated under reduced pressure.The resulting oil contained the two diastereoisomers of (22)and was separated by p.1.c. to give the (2RS,3RS)-alcohoZ(22a; R = Me) (2.4 g, 50%), m.p.148-149" (from chloro-form-petrol), R p 0.6, v,, 3 300 (OH), 1438 (PPh), and1150 cm-l ( P O ) , T (CDC1,) 2.0-2.8 (10 H, m, Ph,PO),4.2br (1 H, s, HC=C), 4.8 (1 H, m, OH), 5.7 (1 H, quint,JpH = JHH = 6 Hz, PC-CHMe), 7.6 (2 H, m, CH,-C=C), 8.0(2 H, m, CH,*C=C), 8.6-9.0 (4 H, m, CH,CH,), 8.95 (3 H,d, J ~ H 18 Hz, PCMe), and 8.95 (3 H, d, JHH 6 Hz,PC*CHMe),m/e 354 (lo%, M+), 337 (5, M - OH), 309 (100, M -MeCHO), and 201 (90, Ph,PO) (Found: C, 74.45; H, 7.85;P, 8.5. C,,H,,O,P requires C, 74.6; H, 7.6; P, 8.7%),and the (2RS,3SR)-alcohoZ (22b; R = Me) (1.4 g, 29%),m.p. 189-191" (from chloroform-petrol), RF 0.5, vmtlX. 3 310(OH), 1440 (PPh), and 1 160 cm-l (P=O), T (CDCl,) 2.0-2.7 (10 H, m, Ph,PO), 4.6br (1 H, s, HC=C), 6.3-6.6 (2H,m, OH and MeCH), 8.0 (2 H, m, CH,*C=C), 8.3 (2 H, m,CH,C=C), 8.5-9.0 (4 H, m, CH,*CH,), 8.7 (3 H, d, JPH18 Hz, I'CMe), and 8.95 (3 H, d, JHH 6 Hz, MeCH), m / e 354(8%, M'), 331 (5, M - OH), 310 (80, - MeCHO), and201 (100, Ph,PO) (Found: C, 74.4; H, 7.8; P, 8.6.C2,H2,02P requires C, 74.6; H, 7.6; P, 8.7%).2-( Cyclohex- l-eny I ) - 2-diphenylphosphinoyl- 1 -phenylpro-pan-l-oE (22; R = Ph).-The olefin (21) (2 g) was stirredunder nitrogen in dry ether (100 ml) while butyl-lithium(6.5 ml; 1 .5 ~ in hexane) was added. The solution wascooled to -78 "C and benzaldehyde (700 mg) in dry ether(25 ml) was added, the red colour being discharged. Thesolution was allowed t o reach room temperature, and water(100 nil) was added.The aqueous layer was extracted withchloroform (3 x 50 ml) and the combined organic layerswere dried (MgSO,) and evaporated under reduced pressure.The oily mixture of diastereoisomers was separated bycolumn chromatography (elution with 1 : 1 ethyl acetate-petrol) to give the (2RS,3SR)-alcohol (22a; R = Ph) (300mg, lZq/,), m.p. 144-147" (from ethyl acetate-di-isopropylether), RF 0.75, vmK 3 300 (OH), 1 440 (PPh), and 1 150 cm-1(P=O), T (CDCl,) 2.0-2.6 (10 H, m, Ph,PO), 2.7 (5 H, s, Ph),3.9 (1 H, s, OH), 4.1 (1 33, m, HC=C), 4.9 (1 H, d, JPH 6Hz,PC*CH-OH), 8.0 (4 H, m, CH,.C=CCH,), 8.6 (4 H, m,CH,CH,), and 9.1 (3 H, d, J ~ H 18 Hz, PCMe), m/e 416 (2%,Ph,POH), and 201 (95, Ph,PO) (Found: C, 78.0; H, 7.2;P, 7.7.C2,H2,0,P requires C, 77.9; H, 7.0; P, 7.4%), andthe (2RSJ3RS)-aZcohol (22b; R = Ph) (1 g , 35%), m.p.209-2 1 1' (from ethyl acetate-di-isopropyl ether), RF 0.6,v,, 3 300 (OH), 1440 (PPh), and 1150 cm-1 ( F O ) , 7M'), 398 (3, M - H,O), 310 (70, M - PhCHO), 202 (100,(CDC1,) 2.0-2.6 (10 H, m, Ph,PO), 2.8 (5 H, s, Ph), 4.4 (1 H,d, JpH 6 Hz, PCCH-OH), 4.7 (1 H, m, CH=C), 5.2 (1 H, m,OH), 8.1 (4 H, m, CH,*C=C*CH,), 8.6 (4 H, m, CH,*CH,),and 8.7 (3 H, d, JPH 18 Hz, PCMe), m/e 416 (2%, M+), 415202 (80, Ph,POH), and 201 (80, Ph,PO) (Found: C, 77.9;H, 6.9; P, 7.4. C,,H,,02P requires C, 77.9; H, 7.0; P,Conversion of the Alcohols (22) into Dienes (23) and theirDiels-Alder Adducts with rMaleic Anhydride.-Each alcohol(22) (200 mg) in diniethylformamide (20 ml) was added tosodium hydride (50 mg of 60% dispersion in oil; washedwith petrol) under nitrogen, and stirred at room temperaturefor 3 h.Water (20 ml) was added slowly and the solutionextracted with petrol (3 x 25 ml). The extracts werewashed with water (6 x 25 ml), dried (MgSO,), and evapor-ated under reduced pressure to give the dienes (23). Eachdiene (40 mg) was heated under reflux in dry benzene (5 ml)with maleic anhydride (60 mg) for 60 h or until reaction wascomplete. The benzene was removed under reducedpressure, and the adducts were collected and recrystallisedfrom toluene-petrol.(Z)-2-CycZohex-l-enylbut-2-eute (23 2; R = Me) (64 mg,80%) was an oil, R p (petrol) 0.5, T (CDC1,) 4.6br (1 H, s,HC=C), 4.8br (1 H, q, J 7 Hz, MeCH=C), 8.0 (4 H, m,CH,-C=C*CH,), 8.3 br (3 H, s, MeC%), 8.5 (3 H, d, J 7 Hz,MeCHZC).The maleic anhydride adduct (26a; R = Me)(50 mg, 70%) had m.p. 60-63", RF 0.8, vmx. 1858 and1 780 cm-l (anhydride), z * (CDCl,) 6.4 (1 H, t, JHR 9 Hz,HC-CO), 6.9 (1 H, dd, J 9 and 2 Hz, HCCO), 7.4 (4 H, m,allylic CH,), 8.3br (3 H, s, MeC=C), 8.5 (6 €3, m, CH,), and8.8 (3 H, d, J 7 Hz, MeCH), m/e 234 (M+, 50%), 206 (60,M - CO), 161 (100, 206 - CO,H) (Found: C, 71.5; H,7.8. C14H1803 requires C, 71.8; H, 7.7%).(E)-2-Cyclohex-l-enyZbut-2-ene (23 E; R = Me) (64 mg,80%) was an oil, RF (petrol) 0.4, T (CDCl,) 4.2br (1 H, s,HC%), 4.5 (1 H, q, J 7 Hz, MeCH=C), 7.8 (4 H, m, CH,.C=CCH,), 8.35 (4 H, m, CH,*CH,), 8.3 (3 H, s, MeC=C), and8.4 (3 H, d, J 7 Hz, MeCH=C).The maleic anhydrideadduct (26b; R = Me) (4.6 mg, 66%) had m.p. 97-99",RF 0.8, vmx. (CHC1,) 1 855 and 1 780 cm-1 (anhydride), T *(CDCI,) 6.7 (2 H, m, CHCO), 7.9 (4 H, m, allylic CH,),8.3br (3 H, s, MeC=C), 8.5 (6 H, m, CH,), and 8.7 (3 H, d, J6 Hz MeCH), m/e 234 (50y0, M+), 206 (60, M - CO), and161 (100, 206 - C0,H) (Found: C, 72.0; H, 7.9%).(Z)-2-CycZohex-l-enyl-l-pJzenyZpvop-1-epze (23 2 ; R = Ph)(68 mg, 70%) was an oil, RF (petrol) 0.5, A,,, 260 (E 3 767)and 266 nm (3 729), T (CDCl,) 2.7br (5 H, s, Ph), 3.3br (1 H,s, PhCH), 4.0 (1 H, m, CH=C), 7.7 (4 H, m, CH,*C%*CH,),8.0 (3 H, s, MeCZC), and 8.3 (4 H, m, CH,CH,), wz/e 198(loo%, -M+) and 183 (70, - Me) (Found: Mf, 198.140 7.ClSHl8 requires M, 198.140 8). The maleic anhydrideadduct (26a; R = Ph) was formed very slowly and couldbe obtained in only tiny amounts. Its n.m.r. spectrum,recorded on the Fourier transform CFT-20 machine at80 MHz, is described in the text.(E)-2-CycZohex-l-enyI-l-~henyZp~o~-l-ene (23 E ; R = Ph)(78 mg, 80%) had m.p. 44-47" Rp (petrol) 0.4, LX(95% EtOH) 271.5 nm (E 16 902), 7 (CDCl,) 2.8 (5 H,m, Ph), 3.8 (1 H, m, PhCH=C), 4.4 (1 H, m, C=CH*CH),8.0br (3 H, s, MeC%), 8.0 (4 H, m, CH,C=CCH,), and 8.3(4 H, m, CH,*CH,), m/e 198 (loo%, M+), 183 (80, M - Me),155 (SO), and 141 (70) (Found: M+, 198.1400. C,,H,,requires M , 198.1408). The maleic anhydride adduct (26a;R = Ph) (40 mg, 70%) had m.p. 128-130", vmX. (CHC1,)(2, M - H), 398 (3, M - HZO), 397 (6), 310 (100, PhZPOEt),7.4%)644 J.C.S. Perkin I1864 and 1782 cm-l (anhydride), T * (CDCl,) 2.7br (5 H,s, Ph), 4.3 (1 H, d, J 6 Hz, PhCHCHCO), 4.6 [2 H, over-lapping ts, J 6 Hz, PhCH*CH(CO)*CH(CO)CH], 6.7 (3 H,m/e 296 (60%, M+), 268 (70, M - CO), 224 (100, 268 -CO,H), and 223 (80) (Found: C, 76.9; H, 6.8. Cl,H,,O,requires C, 77.0; H, 6.7%).rn; allylic CH), 7.7 (8 H, m, CH,), and 7.6 (3 H,-s, MeC%),We thank the S.R.C. for a grant (to A. H. D.).* These n.m.r. spectra are described in the text. [5/1798 Received. 18th September, 1975
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