Abstract:

The structures and energies of various common carbocations, allylic carbocations, and particularly stable α-amino and α-hydroxyl carbocations were calculated using DFT (density functional theory). The results showed that common carbocations are stabilized by the formation of supercovalent structures, rearrangement, and superconjugation effects, whereas allylic carbocations are stabilized by conjugate effects. The stabilities of α-hydroxyl and α-amino carbocations are particularly high and are equivalent to or higher than that of cyclopropylene carbocation. Finally, different methods of carbocation stabilization using amino and hydroxyl groups are suggested.

Key words: Carbocation, Hyperconjugation effect, Super covalent structure, DFT calculation