Intramolecular dihydrogen bond: A new perspective in Lewis acid catalyzed nucleophilic epoxide ring opening reaction

Nucleophilic epoxide ring opening reactions can be effectively carried out with BF3 but not with BH3. This has been traced to the formation of an intermediate with an intramolecular dihydrogen bond which prefers to yield a species with frustrated Lewis acid-base pair after liberating H2 molecule in the BH3 catalyzed system. Quantum chemical analysis indicates that the H2 liberation is more favorable by 37.8 kcal/mol in comparison to the desired aminoalcohol formation.