Geometric Constraints Regulated Regioselectivity: Pd-catalyzed ɑ-Deuteration of Pyridines with Secondary Phosphine Oxide

Abstract

A Pd-catalyzed regioselective H/D exchange at the α-position of pyridines has been achieved by employing secondary phosphine oxide as an internal base. The proposed five-membered structure enabled the reaction to overcome its conventional feature of ortho-directing, allowing the deuteration of pyridines and quinolines at adjacent sites of N-atoms, efficiently.