107. Camphorsulfonamide-Shielded, Asymmetric 1,4-Additions and Enolate Alkylations; Synthesis of a Southern Corn Rootworm Pheromone. Preliminary Communication
     Oppolzer, W.; Dudfield, P.; Stevenson, T.; Godel, T.
     Helv. Chim. Acta 1985, 68, 212-215

Using readily accessible 10-sulfonamido-isoborneols as regenerable, chiral auxiliaries, highly face-selective C–C-bond formations at C_αand C_β of carboxylates could be conveniently achieved. Thus, conjugated additions of RCu to enoates (12) 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.

DOI : 10.1002/hlca.19850680126