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

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 .