Evaluating thiourea/urea catalyst for enantioselective 6π-photocyclintion of acrylanilides

6 pi-Photocyclization of acrylanilide with thiourea and urea based organocatalysts were evaluated to develop H-bonding activated photochemical reactions. These photochemical reactions resulted in a 3,4-dihydroquinolin-2-one photoproduct with low enantioselectivity. Photophysical studies revealed catalyst-substrate interactions in the excited state. The low chiral induction is likely due to a combination of low stereodifferentiation with respect to the mode of cyclization of the substrate by the catalyst, formation of an enol intermediate that destroys the chirality and the relative reactivity of the zwitterionic intermediate that competes with enol formation and direct hydrogen atom migration. (C) 2016 Elsevier B.V. All rights reserved.