A New Preparation of Optically Active N-Acyloxazolidinones via Ruthenium-Catalyzed Enantioselective Hydrogenation Pierre Le Gendre, Patrice Thominot, Christian Bruneau,* and Pierre H. Dixneuf* Lab de Chim de Coord et Catalyse, UMR 6509, Campus de Beaulieu, Universite de Rennes I, 35042 Rennes Cedex, France Received July 16, 1997 R-Methylene-N-acyloxazolidinones are readily prepared in three steps from propargylic alcohols via cyclic carbonates, and the enantioselective hydrogenation of the latter catalyzed by chiral (diphosphine)ruthenium complexes makes possible the obtention of both enantiomers of optically active N-acyloxazolidinones with very high enantioselectivities. Optically active N-acyloxazolidinones are powerful chiral auxiliaries with widespread uses for the synthesis of optically active molecules. 1,2 Their efficiency is due to the fact that their deprotonation at the R-carbon of the N-acyl group gives a (Z)-enolate with high stereoselec- tivity and that the reaction of the latter with a variety of electrophiles leads to stereoselective C-C bond forma- tion via alkylation, 3 acylation 4 and aldol reaction, 5 or C-heteroatom bond formation via halogenation, 6 sulfen- ylation, 7 oxygenation, 8 and amination. 9 When the acyl group contains a conjugated double bond, stereoselective Diels-Alder cycloaddition 10 and Michael addition 11 can be performed. The strength of N-acyloxazolidones is that their chiral oxazolidinone structure, which carries the stereochemical information, can be easily recovered and reused. Optically active oxazolidinones are usually prepared from optically active natural compound derivatives or bifunctional substrates. Natural amino acids are sub- strates of choice for the access to amino alcohols which react with phosgene derivatives to give optically active oxazolidinones. 12,13 Other synthetic processes mainly involve epoxides generated via Sharpless epoxidation of allylic alcohols 14 or -functionalized alcohols such as diols, 15,16 hydroxy azides, 17 and hydroxy esters. 18 We report here a novel route to both enantiomers of optically active N-acyloxazolidinones with very high optical purity, based on the enantioselective hydrogena- tion of N-acyl-4-methylene-1,3-oxazolidin-2-ones cata- lyzed by chiral ruthenium complexes (Scheme 1). Results and Discussion Preparation of the N-Acyl-4-methylene-1,3-oxazo- lidin-2-ones. The unsaturated cyclic carbonates 1, 2 can be selectively prepared from prop-2-yn-1-ols by catalytic reaction with carbon dioxide, 19 and it is known that they readily react with primary amines to generate oxazoli- (1) (a) Evans, D. A.; Bartroli, J.; Shih, T. L. J. Am. Chem. Soc. 1981, 103, 2127. (b) Evans, D. A.; Takacs, J. M., McGee, L. R.; Ennis, M. D.; Mathre, D. J.; Bartroli, J. Pure Appl. Chem. 1981, 53, 1109. (c) Evans, D. A. Aldrichimica Acta 1982, 15, 23. (d) Swern, D.; Dyen, M. E. Chem. Rev. (Washington, D.C.) 1967, 67, 197. (2) Ager, D. J.; Prakash, I.; Schaad, D. R. Chem. Rev. (Washington, D.C.) 1996, 96, 835. (3) (a) Fadel, A. Synlett 1992, 48. (b) Koch, S. S.; Chamberlin, A. R. J. Org. Chem. 1993, 58, 2725. (c) Evans, D. A.; Bilodeau, M. T.; Somers, T. C.; Clardy, J.; Cherry, D.; Kato, Y. J. Org. Chem. 1991, 56, 5750. (d) Kanno, H.; Osamai, K. Tetrahedron Lett. 1995, 36, 5375. (4) (a) Evans, D. A.; Urpi, F.; Somers, T. C.; Clark, J. S.; Bilodeau, M. T. J. Am. Chem. Soc. 1990, 112, 8215. (b) Evans, D. A.; Ennis, M. D.; Le, T.; Mandel, N.; Mandel, G. J. Am. Chem. Soc. 1984, 106, 1154. (5) (a) Shirodkar, S.; Nerz-Stormes, M.; Thornton, E. R. Tetrahedron Lett. 1990, 31, 4699. (b) Evans, D. A.; Bartroli, J. Tetrahedron Lett. 1982, 23, 807. (6) Evans, D. A.; Britton, T. C.; Ellman, J. A.; Dorow, R. L. J. Am. Chem. Soc. 1990, 112, 4011. (7) Chibale, K.; Warren, S. Tetrahedron Lett. 1994, 35, 3991. (8) (a) Evans, D. A.; Gage, J. R. J. Org. Chem. 1992, 57, 1958. (9) (a) Evans, D. A.; Britton, T. C.; Dorow, R. L.; Dellaria, J. F. J. Am. Chem. Soc. 1986, 108, 6395. (b) Trimble, L. A.; Vederas, C. J. J. Am. Chem. Soc. 1986, 108, 6397. (c) Evans, D. A.; Britton, T. C. J. Am. Chem. Soc. 1987, 109, 6881. (d) Harris, J. M.; Bolessa, A. E.; Mendonca, A. J.; Feng, S. C.; Verderas, J. C. J. Chem. Soc., Perkin Trans. 1 1995, 1945. (10) (a) Evans, D. A.; Chapman, K. T.; Bisaha, J. J. Am. Chem. Soc. 1988, 110, 1238. (b) Sugahara, T.; Iwata, T.; Yamaoka, M.; Takano, S. Tetrahedron Lett. 1989, 30, 1821. (11) (a) Kakamura, T.; Hashimoto, N.; Ishizuka, T.; Kunieda, T. Tetrahedron Lett. 1997, 38, 559. (b) Wu, M. J.; Yeh, J. Y. Tetrahedron Lett. 1994, 50, 1073. (12) Davies, S. G.; Polywka, M. E. C.; Sanganee, H. J. Int. Appl. WO 95/18112, 1995. (13) (a) Nicolas, E.; Russel, K. C.; Hruby, V. J. J. Org. Chem. 1993, 58, 766. (b) Wuts, P. G. M.; Pruitt, L. E. Synthesis 1989, 622. (c) Yan, T. H.; Chu, V. V.; Lin, T. C.; Wu, C. H.; Liu, L. H. Tetrahedron Lett. 1991, 32, 4959. (d) Kubota, Y.; Kodaka, M.; Tomohiro, T.; Okuno, H. J. Chem. Soc., Perkin Trans. 1 1993, 5. (e) Imada, Y.; Mitsue, Y.; Ike, K.; Washizuka, K. I.; Murahashi, S. I. Bull. Chem. Soc. Jpn. 1996, 69, 2079. (f) Sakaitani, M.; Ohfune, Y. J. Am. Chem. Soc. 1990, 112, 1150. (14) (a) Juliana, R.; Herzig, T.; Bernet, B.; Vasella, A. Helv. Chim. Acta 1986, 69, 368. (b) Rama Rao, A. V.; Dhar, T. G. H.; Chakraborty, T. K.; Guyar, M. K. Tetrahedron Lett. 1988, 29, 2069. (c) Katsumura, S.; Kondo, A.; Han, Q. Chem. Lett. 1991, 1245. (d) Jung, M. E.; Jung, Y. H. Synlett 1995, 563. (e) Trost, B. M.; Sudhakar, A. R. J. Am. Chem. Soc. 1987, 109, 3792. (f) Iwawa, S.; Katsumura, S. Bull. Chem. Soc. Jpn. 1994, 67, 3363. (15) (a) Georges, M.; Mackay, D. J. Am. Chem. Soc. 1982, 104, 1101. (b) Banks, M. R.; Blake, A. J.; Cadogan, J. I. G.; Dawson, I. M.; Gaur, S.; Gosney, I.; Gould, R. O.; Grant, K. J.; Hodgson, P. K. G. J. Chem. Soc., Chem. Commun. 1993, 1146. (16) (a) Xu, D.; Sharpless, K. B. Tetrahedron Lett. 1993, 34, 5545. (b) Trost, B. M.; Van Vraiken, D. L.; Bingel, C. J. Am. Chem. Soc. 1992, 114, 9327. (17) Sato, T.; Mizutani, T.; Okumura, Y.; Fujisawa, F. Tetrahedron Lett. 1989, 30, 3701. (18) Ghosh, A. K.; Cho, H.; Onishi, M. Tetrahedron: Asymmetry 1997, 8, 821. (19) (a) 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. Scheme 1 1806 J. Org. Chem. 1998, 63, 1806-1809 S0022-3263(97)01733-7 CCC: $15.00 © 1998 American Chemical Society Published on Web 02/20/1998