Photoredox Approach to N-Acyl-N'-aryl-N,N'-aminals Using Enamides and Their Conversion to γ-Lactams.

A photoredox catalytic approach to synthetically valuable N-acyl-N'-aryl-N,N'-aminals is described. This method uses the addition of a radical precursor to enamides, with subsequent interception of the cationic iminium intermediate with an arylamine. The reaction has been shown to be compatible with electron-rich and electron-deficient arylamines, and moderate to good levels of diastereoselectivity can be attained using a chiral enamide. Furthermore, the N-acyl-N'-aryl-N,N'-aminal reaction products can be readily cyclized, providing a novel synthetic route to valuable γ-lactams.