Synthesis of Chiral Isoxazoline Derivatives by Highly Diastereoface-Selective 1,3-Dipolar Cycloaddition of Nitrile Oxides Mediated by Magnesium Bromide and Ytterbium Trifluoromethanesulfonate †
In the presence of an equimolar amount of Lewis acid such as magnesium bromide and ytterbium trifluoromethanesulfonate, 1,3-dipolar cycloaddition reactions of aromatic nitrile oxides to a chiral 3-acryloyl-2-oxazolidinone gave the corresponding chiral 2-isoxazolines in a diastereoselective manner.
Reviews: (a) Advances in Cycloaddition, CurranD.P. (ed.) JAI Press Inc., Greenwich, 1988, Vol 1; 1990, Vol 2; 1993, Vol. 3; (b) 1,3-Dipolar Cycloaddition Chemistry, Padwa, A. (ed.) John Wiley & Sons, Inc.: Toronto, 1984; Vols 1 and 2.
3.
(a) KanemasaS., NishiuchiM., KamimuraA., and HoriK., J. Am. Chem. Soc., 1994, 116, 2324; (b) S. Kanemasa, S. Kobayashi, M. Nishiuchi, H. Yamamoto and E. Wada, Tetrahedron Lett., 1991, 32, 6367.
4.
Parts of these results were reported in 78th National Meeting of the Chemical Society of Japan (4G1 09, 31st March 2000) and Jpn. Kokai Tokkyo Koho, JP 2002-167384 (11th June 2002) [Application No. JP 2000-369628 (30th November 2000)].
5.
YamamotoH., HasegawaM., NoguchiM., and KanemasaS., unpublished data.
6.
In recent years, some approaches for the Lewis acid-supported stereocontrol in nitrile oxide cycloaddition were independently developed. But efficiency of the added Lewis acid was less satisfactory for stereoselection. (a) FaitaG., PaioA., QuadrelliP., RancatiF., and SeneciP., Tetrahedron, 2001, 57, 8313; (b) G. Faita, A. Paio, P. Quadrelli, F. Rancati and P. Seneci, Tetrahedron Lett., 2000, 41, 1265; (c) P. Micúch, L. Fisera, M. K. Cyranski, T. M. Krygowski and J. Krajcik, Tetrahedron, 2000, 56, 5465; (b) P. Micúch, L. Fisera, M. K. Cyranski and T. M. Krygowski, Tetrahedron Lett., 1999, 40, 167.
7.
LiuK. -C., SheltonB. R., and HoweR. K., J. Org. Chem., 1980, 45, 3916.
