Transition metal catalyzed selective B(3)-H or B(4)-H amination of o-carboranes via dehydrogenative BH/NH cross-coupling

A unique approach to vertex-selective catalytic B-H amination at either the B(3)- or B(4)-position in o-carboranes has been developed. Using different transition metal catalysts, dehydrogenative BH/NH cross-coupling of o-carboranes and free amines has been achieved, leading to a wide variety of cage B(3)- or B(4)-aminated o-carboranes in moderate to high yields with excellent regioselectivity, where carboranyl carboxylic acids and amines can serve as competent coupling partners without any pre-functionalization. The isolation and structural identification of a key intermediate provide an insight into the reaction mechanism in the catalytic B(4)-H amination.

Automated summary

A unique approach to vertex-selective catalytic B-H amination has been developed, allowing the reaction to occur at either the B(3)- or B(4)-position in o-carboranes. By using different transition metal catalysts, the dehydrogenative BH/NH cross-coupling of o-carboranes and free amines has been achieved, resulting in a wide variety of B(3)- or B(4)-aminated o-carboranes with high regioselectivity.