Enantioselective organocatalytic Mukaiyama-Michael addition of silyl enol ethers to α,β-unsaturated aldehydes

A highly enantioselective, organocatalytic Mukaiyama-Michael addition reaction of silyl ethers and alpha,beta-unsaturated aldehydes has been developed. The process, catalyzed by MacMillan's chiral imidazolidinone, affords delta-keto aldehydes in high yields (56-87%) and high enantioselectivities (85-97% ee), Moreover, the reaction is applicable to a wide range of silyl ethers and alpha,beta-unsaturated aldehydes and, as such, provides access to a range of important synthetic building blocks.