Diastereo- and Enantioselective Nickel-Catalyzed Intramolecular Reductive Cyclization of Unactivated Alkenes and Aldehydes

Catalytic reductive coupling of unsaturated hydrocarbons with carbonyl compounds provides a streamlined alternative to stoichiometric organometallic additions, yet asymmetric variants that directly engage unactivated alkenes remain limited. Here we report a diastereo- and enantioselective nickel-catalyzed intramolecular reductive cyclization of unactivated alkenes and aldehydes. Using a chiral monodentate phosphoramidite ligand and triethylborane as the terminal reductant, the method delivers substituted cyclic alcohols as single diastereomers in up to 98% yield and up to 99% ee, with broad functional-group tolerance including halides, free alcohols, esters, and boronic esters. Applications to bioactive-molecule synthesis are demonstrated, and DFT studies support an enantiodetermining oxidative cyclization pathway.