Characterization of covalent Ene adduct intermediates in “hydride equivalent” transfers in a dihydropyridine model for NADH reduction reactions

► An NADH model study with α,β-unsaturated cyano and carbonyl substrates. ► All reactions involve an initial covalent Ene adduct between the two reactants. ► In acetone-d6/water solutions all reactions produce reduced substrates. ► The Ene adduct provides a model for a transition state shape for NADH reactions.