Rhodium-catalyzed one-pot tandem reductive amination/asymmetric transfer hydrogenation of quinoxaline-2-carbaldehydes and anilines for the efficient synthesis of chiral vicinal diamines†

Abstract

Enantioselective synthesis of chiral N,N′-diaryl vicinal diamines via Cp*Rh-catalyzed one-pot tandem reductive amination/asymmetric transfer hydrogenation of quinoxaline-2-carbaldehydes with anilines using HCO₂H/NEt₃ (5/2) as the reductant has been developed. This mild catalytic system exhibits broad substrate generality and efficiently produces diversely substituted chiral N,N′-diaryl vicinal diamines with opposite configurations in high yields and excellent enantioselectivities (up to >99% ee). The synthetic utility of this protocol has been validated through successful gram-scale synthesis and facile derivatization of the resulting chiral vicinal diamines.