Development of Highly Effective Encapsulating Surfactants for Mukaiyama Aldol Reactions in Water

Abstract

Amphiphilic calix[6]arene derivatives 1a−b and calix[4]arene 1d−1e, as well as aliphatic (2a−b) and aromatic (2c−2d) anionic surfactants, were studied for their encapsulating ability in stabilizing water-sensitive compounds. They were found to be efficient surfactants for Sc(OTf)3-catalyzed Mukaiyama aldol reactions of labile enol ethers with aldehydes in water. The results indicate that a hydrophobic microenvironment was formed in the reaction system with either the amphiphilic calix[6]arene derivatives or the simple aromatic surfactants, which could encapsulate and stabilize some labile silyl enol ethers and thus promote the reactions.