Enantioselective Construction of 6–10-Membered Cyclic Allylic Alcohols Containing Exocyclic Alkenes by Synergistic Photoredox/Cobalt-Catalyzed Intramolecular Alkenylation of Aldehydes

A synergistic photoredox/cobalt-catalyzed protocol for the construction of 6–10-membered allylic alcohols through enantioselective intramolecular alkenylation of aldehydes is presented. Such processes enabled access to a variety of medium-sized rings bearing exocyclic double bonds and application in the simultaneous establishment of central and axial stereogenicity, representing a general platform for the synthesis of enantioenriched cyclic allyl alcohols with diverse ring sizes. Mechanistic studies and DFT calculations elucidated the involvement of an alkenyl radical intermediate and models of stereochemical induction.