Theoretical study on reaction mechanism of desymmetrization of meso anhydrides catalyzed by bifunctional Bronsted Acid/Base organocatalyst

초록

The reaction between anhydride and methanol catalyzed by bifunctional Bronsted acid/base organocatalyst was investigated theoretically by B3LYP method with 6-31++G* basis set. Calculations indicate that the energy barrier is quite high without catalyst, i.e. 30.8 kcal/mol. In the presence of catalyst, the reaction proceeds through a concerted mechanism with the energy barrier of 14.1 kcal/mol. The pyridine moiety works as a Bronsted base to activate methanol substrate, and the N atom attached to P atom works as a Bronsted acid to activate anhydride by hydrogen bonding.