Iron-Catalyzed Enantioselective Deoxygenative Addition of Propargyl, Allyl, and Benzyl Alcohols to Cyclic N-Sulfonyl α-Ketiminoesters Mediated by Visible Light.

Asymmetric photomediated iron catalysis remains underdeveloped; up to now, only limited successful examples have been reported. Herein, we describe an iron-catalyzed enantioselective deoxygenative addition of propargyl, allyl, and benzyl alcohols to cyclic N-sulfonyl α-ketiminoesters mediated by visible light, providing straightforward access to a diverse array of chiral cyclic sulfonamides. This approach addresses several synthetic limitations in entioselective transformation of cyclic N-sulfonyl α-ketiminoesters, including the limited development of general and efficient asymmetric propargylation methods, and the limited structural diversity in allylation products. The synthetic versatility of this method is demonstrated through the preparation of a number of valuable intermediates. Preliminary density functional theory (DFT) calculations on the radical addition pathway suggest that the observed enantioselectivity primarily arises from steric interactions between the incoming radical and the 4-chlorophenyl ring on the chiral ligand.