Organocatalytic atropo- and E/Z-selective Michael addition reaction of ynones with α-amido sulfones as sulfone-type nucleophile

Abstract

We describe herein the first enantioselective organocatalytic Michael addition reaction of α-amido sulfones to ynones to access axially chiral styrenes. Sulfone-containing axially chiral styrene compounds were constructed with excellent enantioselectivity and almost complete E/Z-selectivity (up to 97% ee, >20 : 1 E/Z) in the presence of an easily accessible cinchona-alkaloid-derived multiple hydrogen-bonding catalyst. The enantioenriched sulfone-containing products were used as precursors for further transformations without any loss of the ee value. The equilibration process of this transformation was monitored by ¹H NMR spectroscopy.