Enantioselective NHC-Catalyzed Redox [2+2] Cycloadditions with Perfluoroketones: A Route to Fluorinated Oxetanes

Abstract

The N-heterocyclic carbene (NHC) catalyzed redox formal [2+2] cycloaddition between α-aroyloxyaldehydes and perfluoroketones, followed by ring-opening in situ delivers a variety of perfluorinated β-hydroxycarbonyl compounds in good yield, and excellent diastereo- and enantioselectivity. Through a reductive work-up and subsequent cyclization, this protocol offers access to highly substituted fluorinated oxetanes in two steps and in high ee.

Keywords: Lewis base; N-heterocyclic carbene; organocatalysis; oxetane; pentafluoroethyl.