Alkali metal catalyzed dehydro-coupling of boranes and amines leading to the formation of a B–N bond

Abstract

In this report we describe catalytic B–N bond formation via cross-dehydrocoupling (CDC) of boranes with amines to construct aminoboranes with a high degree conversion (>90%) and chemo-selectivity using alkali metal hexamethyldisilazides [MN(SiMe₃)₂] (M = Li, and K) as pre-catalysts. It was observed that the lithium and potassium hexamethyldisilazides proved to be an effective pre-catalyst for aliphatic primary, secondary amines, aromatic primary, and substituted amines. The catalyzed cross-dehydrocoupling reaction using [MN(SiMe₃)₂] (M = Li and K) as a pre-catalyst displayed a broad substrate scope. Pinacolborane smoothly reacted with a number of aliphatic and aromatic amines under ambient conditions whereas a prolonged reaction time of around 8–12 hours was required for 9-BBN to undergo CDC reactions.