BORNANESULTAM-DIRECTED ASYMMETRIC-SYNTHESIS OF CRYSTALLINE, ENANTIOMERICALLY PURE SYN ALDOLS

N-acylsultams 2 furnish, via aldolization of their enolates 16 with aldehydes, diastereomerically pure, crystalline syn aldols. The absolute configuration of the product is controlled by the choice of the enolate counterion: 16, M = B⊒ 3; 16, M = Li or Sn(IV) ⊒ 5. Hydroperoxide-assisted hydrolysis/esterification or reductive cleavage provided enantiomerically pure methoxycarbonyl aldols (12 and 13) or 1,3-diols (11) with recovery of auxiliary 1. The chiral serricornin precursor 14 was thus prepared. © 1993, IEEE. All rights reserved. © 1990, American Chemical Society. All rights reserved.