Ni-Catalyzed Diastereoconvergent Intramolecular Alkene–Aldehyde Reductive Coupling: A Route to syn-Chromanols

Abstract

We demonstrate for the first time a nickel-catalyzed diastereoconvergent reductive coupling of a heteroatom-attached allyl moiety with aldehydes, viz., O-allyl, O-cinnamyl salicylaldehydes, and others, to afford syn-chromanols exclusively. The reaction proceeds through a [2 + 2 + 1] oxidative cycloaddition involving the active catalyst. This method is applicable to both terminal and internal olefin substrates. The formal syntheses of have been demonstrated. Control experiments, mass spectrometric analysis, and DFT studies supported the plausible mechanism and the origin of exclusive synselectivity.