Electronic Structures and Reactivities of Pyramidal Alkenes and Carbonyls

Theoretical predictions that alkenes and carbonyls pyramidalize in asymmetric environments were made before any conclusive experimental evidence for this phenomenon had been noted. In the last two years, several such pyramidalizations have been discovered. This review summarizes the predictions, experimental discoveries, and theoretical explanations of pyramidalizations of alkene and carbonyl carbons and describes the evidence indicating that both pyramidalization and stereoselectivity in reactions of such molecules arise from torsional (closed‐shell repulsion) effects.