Camphorsulfonamide‐Shielded, Asymmetric 1,4‐Additions and Enolate Alkylations; Synthesis of a Southern Corn Rootworm Pheromone. Preliminary Communication

Abstract

Abstract Using readily accessible 10‐sulfonamido‐isoborneols as regenerable, chiral auxiliaries, highly face‐selective C–C‐bond formations at C α and C β of carboxylates could be conveniently achieved. Thus, conjugated additions of RCu to enoates ( 1 → 2 ) furnished, after saponification, β‐substituted carboxylic acids 3 in 94–98% e.e. Similarly, propionates 12 yielded after deprotonation, enolate alkylation, and reductive ester cleavage the ( R )‐alcohols 15 in 78–98% e.e. The acid (+)‐ 3e was converted to the pheromone (–)‐ 11 .