Stereocontrol of intramolecular Diels–Alder reactions by an allylic diphenylcyclopropyl group
作者:Regis Tripoli、Tory N. Cayzer、Anthony C. Willis、Michael S. Sherburn、Michael N. Paddon-Row
DOI:10.1039/b708324f
日期:——
Intramolecular DielsâAlder reactions of ester-linked 1,3,8-nonatrienes carrying a diphenylcyclopropyl substituent attached to C1 proceed with high levels of stereoselectivity. The stereochemical outcomes of these reactions are explained by reference to B3LYP/6-31G(d) transition structures. Experimentally, the diphenylcyclopropane rings remain intact through these IMDA reactions, notwithstanding their predicted extremely high degree of asynchronicity (the B3LYP-computed lengths in the IMDA transition structures differ by as much as 1.1 Ã ), providing support to the notion that these reactions are concerted processes.