Nanoconfinement Effects of Micellar Media in Asymmetric Catalysis

Abstract

Replacement of organic solvents, in particular chlorinated, aromatic, and polar aprotic ones, is an emerging issue that can find a solution in the development of catalytic reactions in water. Nature performs a multitude of chemical transformations in water under mild conditions mediated by enzymes. In particular the nanoconfinement effects of the enzymes ensure high activity and impressive stereoselectivities. Micellar catalysis is nowadays a real alternative approach to catalysis in traditional organic media, enabling good activity under mild conditions, with the advantage of possible catalyst and micellar medium recycling. Micellar media emerged also as good nano-environments for stereoselective reactions, with many examples of chemical transformations mediated by metal and organo-catalysts for which improvements of stereoselectivity were observed with respect to the same reaction under homogeneous conditions in traditional organic solvents. More specifically, both the catalytically active site and the micelles provided by the surfactant can contribute to the asymmetric induction, partially resembling what known in terms of stereoselectivity imparted by the active site of enzymes and metallo-enzymes. (Figure presented.).