Carbonyl coordination chemistry from a new angle: A computational study of alpha-carbon acidity based on electrophile coordination geometry

摘要

The dependence of acidity on Li-circle plus coordination geometry to alpha-carbon acids is investigated by generating potential energy surfaces of Li-circle plus complexation with acetaldehyde and its respective enolate. The global minimum for the enolate complex shows significant Li-circle plus-pi-system coordination to both oxygen and the alpha-carbon. The gas-phase acidity analysis reveals significantly more alpha-carbon coordination, which presumably enhances the lability of the cleaving proton in the transition state of deprotonation.