NHC-Silyliumylidene Cation-Catalyzed Hydroboration of Isocyanates with Pinacolborane.

The low-oxidation-state silicon-catalyzed hydroboration of isocyanates with pinacolborane (HBpin) using the NHC-silyliumylidene cation catalyst [(IMe) 2 SiH]I ( 1 , IMe = :C{N(Me)C(Me)} 2 ) is described. In the catalysis, the Si lone pair electrons activate isocyanates, and the latter react with HBpin to form N -boryl formamides at room temperature. Catalyst 1 further activates N -boryl formamides at 70 °C, the intermediates of which react with HBpin to form N -boryl methylamines and (pinB) 2 O.