Transition-Metal-Free C‑Vinylation of Ketones with Acetylenes: A Quantum-Chemical Rationalization of Similarities and Differences in Catalysis by Superbases MOH/DMSO and <i>t</i>BuOM/DMSO (M = Na, K)

Transition-metal-free C-vinylation of acetone with phenylacetylene catalyzed by superbases MOH/DMSO and <i>t</i>BuOM/DMSO (M = Na, K) has been theoretically evaluated in the B3LYP/6-311++G**//B3LYP/6-31+G* approach to rationalize similarities and differences in activity of the above catalytic systems. The close solvate surroundings of sodium and potassium <i>tert-</i>butoxides have been studied. Formation of <i>t</i>BuOM·<i>n</i>DMSO complexes and their structure and thermodynamic stability are discussed in comparison with similar complexes of alkali-metal hydroxides MOH·<i>n</i>DMSO. Activation barriers of the title reaction in the presence of <i>t</i>BuOM·<i>n</i>DMSO complexes are found to be less than those with MOH·<i>n</i>DMSO complexes participating