Manganese(I)-catalyzed dehydrogenative borylation of terminal alkynes

Abstract

Compounds containing carbon−boron bonds serve as valuable intermediates for constructing more complex molecules by transforming these bonds into other carbon−element bonds. The catalytic dehydrogenative borylation of carbon−hydrogen bonds using HBpin presents an appealing method for synthesizing carbon−boron bonds. While this approach has been extensively explored with noble metals for various types of carbon−hydrogen bonds, its application with manganese-based catalysts remains rare. This study explores a dehydrogenative borylation process employing an earth-abundant transition metal catalyst, FcbpyMn(CO)₃Br (Mn(I)), in combination with HBpin under mild conditions. Arylalkynes featuring electron-withdrawing, electron-donating, and heteroaryl substituents yielded good to excellent results. A thorough DFT calculations were done to understand the mechanism.