SYNTHESIS OF 2-ISOXAZOLINES FROM OLEFINS DERIVED FROM NOREPHEDRINE AND PULEGONE

In this communication we report the use of (+/-)-norephedrine and (-)- 8-benzylaminomenthol (derived from (+/-)-pulegone) as chiral adjuvants far the cycloaddition of alpha,beta-unsaturated 1,3-dipolarophiles. 2 -Isoxazolines were obtained with low stereoselectivity born the reacti on of nitrile oxides with the N-tosyl norephedrine derivative as the d ipolarophile. Cycloaddition of nitrile oxide with 2-vinyl-N-benzyl-4,4 ,7 alpha-trimethyl-trans-octahydro-1,3-benzoxazine produced stereoisom eric 2-isoxazolines in a ratio of about 95:5. (C) 1998 Elsevier Scienc e Ltd. All rights reserved.