Orbital phase environments and stereoselectivities

Abstract

Facial selections are reviewed to propose a new theory, orbital phase environment, for stereoselectivities of organic reactions. The orbital phase environment is a generalized idea of the secondary orbital interaction between the non-reacting centers and the unsymmetrization of the orbitals at the reacting centers arising from in-phase and out-of-phase overlapping with those at the neighboring non-reacting sites. In this context, the nucleophilic addition preferentially occurs on the face of the carbonyl functionality opposite to the better electron-donating orbital at the β position. In a similar manner to the carbonyl cases, the preferred reaction faces of olefins in electrophilic addition reactions are opposite to the better electron-donating orbitals at the β positions. The orbital phase environments in Diels-Alder reactions are also reviewed. © Springer-Verlag Berlin Heidelberg 2009.