Insight into Markovnikov regioselectivity rule via molecular face and ABEEM-σπ theory

Abstract

Electrophilic additions of HCl to a series of asymmetric alkenes in the gas phase are investigated by the Molecular Face (MF) theory and ABEEM-σπ model. The interesting features of regioselectivity for these reactions are characterized by the electron density (ED) encoded on the MF of alkenes and charge distribution of alkenes obtained via the ABEEM-σπ model, respectively. It is then demonstrated that for a series of alkenes, the Hammett constant σp (substituent constant) has a good linear correlation with KED, where KED is character of the ED at the π region in the initial state of alkenes. Comparison between investigations using MF, ABEEM-σπ, molecular electrostatic potential, and DFT theories, in essence, give similar conclusions for explaining the regioselectivity of the electrophilic additions to alkenes, although from different points of view. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011