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J. Org. Chem. 1996, 61, 4516-4519
Articles Synthesis of Highly Functionalized γ-Butyrolactones from Activated Carbonyl Compounds and Dimethyl Acetylenedicarboxylate† Kyoko Nozaki,* Naomasa Sato, Kazuhiro Ikeda, and Hidemasa Takaya*,‡ Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Yoshida, Sakyo-ku, Kyoto, 606-01, Japan Received October 11, 1995X
A triphenylphosphine-catalyzed cyclization of R-keto esters, R-keto nitriles, or R,R,R-trifluoroacetophenone with dimethyl acetylenedicarboxylate is reported to produce highly functionalized R,βunsaturated γ-butyrolactones in moderate yields. Thus treating a mixture of methyl 4-nitrophenylglyoxylate and dimethyl acetylenedicarboxylate with 20 mol % of triphenylphosphine afforded 5,5′-disubstituted 3-methoxy-4-(methoxycarbonyl)-2(3H)-furanone in 94% yield. In the reaction of R-keto esters R1COCOOMe, an electron-withdrawing R1 substituent is required for satisfactory reactivity. On the other hand, electron-donating R1 substituents give higher yields with R-keto nitriles R1COCN. Another electron-deficient carbonyl compound, R,R,R-trifluoroacetophenone, gave the corresponding lactone in good yield. The use of an R-hydroxy ketone as an electrophilic carbonyl compound with more than 1 equiv of triphenylphosphine produced dihydrofuran derivatives. One equivalent of triphenylphosphine oxide was obtained as a major product. An intramolecular Wittig reaction is proposed as a reaction mechanism. Introduction Organophosphorus compounds are widely used in organic synthesis.1 When they act as a catalyst, “soft” nucleophilicity is one of their most characteristic features, as shown in the Michael addition,2 aldol condensation,3 isomerization of C-C mutiple bonds,4 silylcyanation of aldehydes,5 alcohol addition to methyl propiolate,6 carbonate formation from propargyl alcohol and carbon dioxide,7 and cycloaddition of 2,3-butadienotes or 2-butynoates with electron-deficient olefins.8 In 1966, Winsterfeldt reported a triphenylphosphine-catalyzed lactone formation from benzaldehyde and dimethyl acetylenedicarboxylate in less than 20% yield.9 The proposed mechanism is shown in Scheme 1, which includes zwitterionic intermediate A.10 A number of organic trans† Dedicated to Clayton H. Heathcock on the occasion of his 60th birthday. ‡ Deceased Oct 4, 1995. X Abstract published in Advance ACS Abstracts, June 1, 1996. (1) Organic Phosphorus Compounds; Kosolapoff, G. M., Maier, L., Eds.; Willey-Interscience, a division of John Wiley & Sons, Inc. (2) Miyakoshi, T.; Omichi, H.; Saito, S. Nippon Kagaku Kaishi 1980, 44. (3) Miyakoshi, T.; Omichi, H.; Saito, S. Nippon Kagaku Kaishi 1979, 748. (4) (a) Trost, B. M.; Kazmaier, U. J. Am. Chem. Soc. 1992, 114, 7933. (b) Trost, B. M.; Li, C. J. Am. Chem. Soc. 1994, 116, 3167. (c) Trost, B. M.; Li, C. J. Am. Chem. Soc. 1994, 116, 10819. (d) Guo, C.; Lu, X. J. Chem. Soc., Perkin Trans. 1 1993, 1921. (e) Guo, C.; Lu, X. J. Chem. Soc., Chem. Commun. 1993, 394. (5) Kobayashi, S.; Tsuchiya, Y.; Mukaiyama, T. Chem. Lett. 1991, 537. (6) Inanaga, J.; Baba, Y.; Hanamoto, T. Chem. Lett. 1993, 241. (7) Fournier, J.; Bruneau, C.; Dixneuf, P. H. Tetrahedron Lett. 1989, 30, 3981. (b) Joumier, J. M.; Fournier, J.; Bruneau, C.; Dixneuf, P. H. J. Chem. Soc., Perkin Trans. 1 1991, 3271. (8) Zhang, C.; Lu, X. J. Org. Chem. 1995, 60, 2906. (9) Winterfeldt, E.; Dillinger, H.-J. Chem. Ber. 1966, 99, 1558. (10) White, N. E.; Allen, D. W.; Tebby, J. C. Phosphorus 1971, 1, 139.
S0022-3263(95)01828-7 CCC: $12.00
Scheme 1
formations of intermediate A were demonstrated by Tebby,11 but its use in a catalytic cycle has as yet been limited. R-Keto esters and R-keto nitriles have electronwithdrawing groups directly bound to their ketonic carbonyl groups. The strong electrophilic nature of these ketonic groups is expected to facilitate various kinds of nucleophilic additions.12 We became interested in the use of these activated carbonyl compounds as trapping reagents for the zwitterionic intermediate A. In this paper, we report a triphenylphosphine-catalyzed cyclization of R-keto esters, R-keto nitriles, or R,R,R-trifluoroacetophenone with dimethyl acetylenedicarboxylate (2) to produce highly functionalized R,β-unsaturated γ-butyrolactones 3 in moderate to good yields. A related cyclization of R-hydroxy ketones 4 with acetylenedicarboxylate 2 is also described. The latter reaction is proposed to proceed via an intramolecular Wittig reaction. (11) For example, see: Tebby, J. C.; Wilson, I. F.; Griffiths, D. V. J. Chem. Soc., Perkin Trans. 1 1979, 2133. (12) For a review for R-keto nitriles, see: Hu¨nig, S.; Schaller, R. Angew. Chem., Int. Ed. Engl. 1982, 21, 36.
© 1996 American Chemical Society
Synthesis of Highly Functionalized γ-Butyrolactones
J. Org. Chem., Vol. 61, No. 14, 1996 4517
Table 1. Tertiary Phosphine-Catalyzed Lactone Formation from Electron-Deficient Carbonyl Compounds 1 and Dimethyl Acetylenedicarboxylate (2) run
substrate 1
R1
R2
phosphines
time (h)
yield of 3 (%)a,b
1 2 3 4 5 6 7 8 9 10 11 12 13 14
1a 1b 1c 1d 1e 1f 1g 1h 1i 1j 1k 1a 1a 1a
4-NO2C6H4 Ph 4-ClC6H4 Ph 4-MeC6H4 4-MeOC6H4 4-ClC6H4 4-NO2C6H4 c-C6H11 Ph Ph 4-NO2C6H4 4-NO2C6H4 4-NO2C6H4
COOMe COOMe COOMe CN CN CN CN CN CN CH3 CF3 COOMe COOMe COOMe
PPh3 PPh3 PPh3 PPh3 PPh3 PPh3 PPh3 PPh3 PPh3 PPh3 PPh3 (S)-BINAPf (R)-MeO-MOPg (+)-NMDPPh
22 8 22 8 19 19 22 22 22 22 17 49 47 48
94 11c-e c 58 58 67 30d
