Energy Decomposition Analysis Reveals the Nature of Lone Pair−π Interactions with Cationic π Systems in Catalytic Acyl Transfer Reactions

Lone pair−π (LP−π)
interactions between
Lewis basic heteroatoms, such as oxygen and sulfur, and electron-deficient
π systems are important noncovalent interactions. However, they
have seldom been used to control catalyst–substrate interactions
in catalysis. We performed density functional theory calculations
to investigate the strengths of LP−π interactions between
different lone pair donors and cationic π systems, and in different
complexation geometries. Energy decomposition analysis calculations
indicated that the dominant stabilizing force in LP−π
complexes is electrostatic interaction and the electrostatic potential
surface of the π system predicts the most favorable site for
forming LP−π complexes. Benzotetramisole (BTM) is revealed
as a privileged acyl transfer catalyst that promotes LP−π
interactions because the positive charge of the acylated BTM is delocalized
onto the dihydroimidazole ring, which binds strongly with a variety
of oxygen and sulfur lone pair donors.