Synthesis of (-)-Phaseolinic Acid

Abstract

The synthesis of (-)-phaseolinic acid exemplifies a procedure for the Cu(I)-catalyzed asymmetric 1,4-addition of Grignard reagents to α,β-unsaturated thioesters followed by aldol reaction of the resultant magnesium enolates with aldehydes to give syn,syn-stereotriads with excellent diastereo- and enantioselectivity. The method is a rare example of the asymmetric conjugate addition of an organometallic reagent to an acyclic α,β-unsaturated carbonyl derivative.