Role of charge-transfer effects in regioselectivity

摘要

The energy-partitioning scheme was used to study the regioselectivity problem. As a model system, Diels-Adler (DA) reaction was considered. It is shown that charge-transfer (CT) energy is not responsible for experimentally observed trends in regioselectivity. However, it is the only contribution to the overall interaction energy that depends regularly on the type of substituents attached to reactant molecules. The main factors governing the orientation in DA reaction are deformation and Heitler-London energies. We have also demonstrated that the clear relationship between CT energy and the amount of charge transferred from one to another reactant exists for reactive systems that differ only in the substitution pattern. (C) 2004 Wiley Periodicals, Inc.