Crystallographic Evidence for Cyclopropane Ring Formation inIsotwistenes Obtained by Thermal Cascade Reactions ofCyclopentadienone with Acyclic Conjugated Dienes

摘要

The molecular structure of the double Diels—Alder (DDA) adduct derived from three-step thermal cascadereactions of 2,5-bis(methoxycarbonyl)-3,4-diphenylcyclopentadienone with ethyl sorbate is elucidated by singlecrystal X-ray analysis. The structural features and the reaction mechanism of the adduct are discussed on thebasis of density functional theory (DFT) calculation results.