On the non-planarity of 1,3-dioxole and 1,3-dioxolane

The conformational preferences of 1,3-dioxole and 1,3-dioxolane are explained on the basis of the QTAIM electron density analysis of B3LYP/6-311++G(2d,2p) electron distributions, supporting the interpretation of the anomeric effect previously proposed by Vila and Mosquera [14]. Thus, distances from methylenic hydrogens to oxygen lone pairs and H–C–O-lp dihedral angles sufficiently explain the atomic population and energy variations, thereby explaining the ring puckering preference.