Enantioselective synthesis of α-nitro-δ-ketosulfones via a quinine-squaramide catalyzed conjugate addition of α-nitrosulfones to enones

Abstract

Conjugate addition of α-nitrosulfones to vinyl ketones in the presence of 0.2 mol% of a quinine-squaramide organocatalyst afforded α-nitro-δ-ketosulfones possessing a tetrasubstituted chiral center in excellent yield and enantioselectivity in most cases. This strategy also offers a facile and convenient entry into γ-sulfonylhydroxamates that are one carbon homologs of potent enzyme inhibitors. © 2013 The Royal Society of Chemistry.