Continuous Flow α-Arylation of N,N-Dialkylhydrazones under Visible-Light Photoredox Catalysis

The first direct alpha-arylation of aldehyde-derived N,N-dialkylhydrazones with electron deficient aryl and heteroaryl cyanides under visible-light photoredox catalysis has been developed. Structurally complex alpha,alpha'-diaryl-N,N-cycloalkylhy-drazones were obtained in moderate yields by repetition of the direct arylation protocol. A continuous-flow procedure for the preparation of alpha-aryl-N,N-dialkylhydrazones on a multigrarn scale has also been established.