Microwave activation of an asymmetric Michael reaction: unexpected behaviour of chiral α-alkoxy imines

Abstract

While it has been previously established that chiral α-alkoxy imines undergo thermal rearrangement at temperatures above 50°C, the microwave activation of the Michael addition between chiral imine 3b and methyl acrylate at 100°C led cleanly to the corresponding Michael adduct 5b without the formation of any rearranged product and with the same regio- and stereoselectivity as the corresponding thermal condensation at 40°C (ee 95%).