Second-Layer Chiral Environment-Induced Steric Hindrance Enables Catalyst Conformation Lockdown in Enantioselective Hypervalent Iodine Organocatalysis

A class of confined chiral hypervalent iodines have been designed and developed by incorporating two sterically demanding BINOL-derived units, which form the second-layer chiral environment, into the iodine-containing molecules to lock down the conformation of the catalyst and indirectly create a compact chiral environment around the active site. Good-to-excellent enantioselectivities have been achieved with these catalysts for the α-oxysulfonylation of ketones (up to 97.5:2.5 er) and the oxidative cyclization of 5-oxo-5-arylpentanoic acids to γ-butyrolactones (up to 98:2 er), thereby demonstrating the utility of this strategy for catalyst design.