Stereoelectronic Properties, Stereospecificity and Stabilization of α‐Seleno Carbanions. An ab initio Study

Abstract

Abstract An ab initio study of α‐seleno carbanions show that they are subject to appreciable polarization and stereoelectronic effects. Like in α‐thia carbanions, the equatorial e forms are more stable than the axial a forms, one of the stabilizing contributions being the conformation dependent (C‐lone pair, σ* SeZ) interaction. The carbanion stabilizing effect of the α‐Se atom is about 3 kcal/mol larger than that of the sulfur analog. As in the case of the sulfur no specific effect of the d orbitals is found.