FeCl₃-Promoted [3 + 2] Annulations of γ-Butyrolactone Fused Cyclopropanes with Heterocumulenes

摘要

The [3 + 2] annulations of γ-butyrolactone fused donor–acceptor (D–A) cyclopropanes with aromatic isothiocyanates and dialkyl carbodiimides promoted by FeCl_(3) is reported. A series of bicyclic/polycyclic γ-butyrolactone fused thioimidates and γ-butyrolactone fused amidines containing four contiguous stereogenic centers were obtained in excellent yields as single stereoisomers.