Origins of regio- and stereoselectivity in Cu-catalyzed alkyne difunctionalization with CO2 and organoboranes

Abstract

The mechanism and origins of regio- and stereoselectivities of Cu-catalyzed alkyne difunctionalization with CO₂ and trialkyl boranes were computationally investigated. The results show that the vicinal addition to alkyne is disfavored due to the kinetical inertness of the alkyl copper intermediate. The favored geminal addition proceeds through the cationic Cu-mediated stereoselective 1,2-migration pathway. The energy decomposition analysis indicates that the σ)(π Pauli repulsion is the dominant factor for controlling the stereoselectivity.