Mild catalytic deoxygenation of amides promoted by thorium metallocene

Abstract

The organoactinide-catalyzed (Cp*₂ThMe₂) hydroborated reduction of a wide range of tertiary, secondary, and primary amides to the corresponding amines/amine–borane adducts via deoxygenation of the amides is reported herein. The catalytic reactions proceed under mild conditions with low catalyst loading and pinacolborane (HBpin) concentration in a selective fashion. Cp*₂ThMe₂ is capable of efficiently catalysing the gram-scale reaction without a drop in efficiency. The amine–borane adducts are successfully converted into free amine products in high conversions, which increases the usefulness of this catalytic system. A plausible mechanism is proposed based on detailed kinetics, stoichiometric, and deuterium labeling studies.