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. Thorough DFT calculations were performed to understand the mechanism.