Cyclic Iodine Reagents Enable Allylic Alcohols for Alkyl Boronate Addition/Rearrangement by Photoredox Catalysis

All-carbon quaternary centers are prevalent in bioactive small molecules. However, their efficient construction remains a formidable synthetic challenge. Here we report cyclic iodine(III) reagents enable the synthesis of cyclopentanones, cyclohexanones, and dihydrofuranones bearing alpha-quaternary centers by photoredox catalysis. The reaction proceeds by the formation of the novel cyclic iodine(III) reagent-allylic alcohol complex, which enables the first alkyl boronate addition and semi-pinacol rearrangement of allylic alcohols with dual alcohol and olefin activation. The reaction is suitable for gram scale synthesis and is transformable to alcohols, olefins, oximes, and lactones with an alpha-quaternary center in one step.