Umpolung Reactivity of Imine Ester: Visible-Light Mediated Transfer Hydrogenation of α-Aryl Imino Esters by Phenylsilane and Water.

A visible-light mediated chemoselective transfer hydrogenation of α-aryl imino esters was demonstrated. The methodology allowed the efficient and practical preparation of α-amino acid esters. The mechanism of the reaction was probed by DFT calculations, and deuteration experiments indicated deuterium was introduced into amino acid esters efficiently (up to 99 % D ratio), enabling a feasible way to obtain deuterated amino acids using D O as a cheap deuterium source.