Pyridine Hydroboration with a Diazaphospholene Precatalyst

Abstract

We demonstrate pyridine hydroboration catalyzed by a diazaphospholene hydride precatalyst. Pyridines bearing electron-withdrawing groups in the 3-position are hydroborated efficiently. This system features low catalyst loadings, fast reaction times at ambient temperature, and tolerance of other reducible functionality. Off-cycle products of pyridine hydrophosphination were also obtained in one case from a stoichiometric reaction and structurally characterized.