Enantioselective Catalytic Addition of N-Acyl Radicals: In Batch and In Flow Organophotoredox α-Amination of Aldehydes

Abstract

The organophotoredox catalytic enantioselective addition of N-acyl radicals to aldehydes, to afford enantioenriched N-acyl 1,2 aminoalcohols was studied. Under the best conditions, in batch, the product was isolated in up to 52 % yield and 85 % e.e., using a low cost and commercially available chiral imidazolidinone as organocatalyst. The reaction was then studied in flow, exploring different experimental setups and photoreactors. Although modest yields were obtained, the in-flow process afforded the product in higher productivities (up to 60 times higher) and improved space time yields (increased up to 113 times) compared to the batch reaction, with no loss of stereoselectivity.