Quantum chemical comparison of ethynylation and C-vinylation routes in superbase catalyzed reaction of acetylenes with imines

The kinetic (free activation energies) and thermodynamic factors, which ensure mild conditions for the ethynylation of imines with acetylenes, have been established by quantum chemical calculations using B2PLYP/6-311+G**//B3LYP/6-31+G*. According to the calculations, the alternative route of superbase catalyzed C-vinylation requires harsher reaction conditions as compared to the ethynylation one.