An X~-(X=I, Br)-Triggered Ring-OpeningCyclization of Cyclopropenyl-Substituted AlkylHalides or Mesylates: An Efficient and Highly Regio-and Stereoselective Approach to (E)-Haloalkylidene4-7-Membered Cyclic Compounds

摘要

Polyfunctionalized (E)-haloalkylidene cyclic products wereefficiently synthesized in moderate to excellent yields via aregio- and stereoselective X~-(X = I or Br)-triggered ring-opening intramolecular trapping of cyclopropenes 1. Thereaction can be used for construction of 4-7-memberedproducts. The E-stereoselectivity of the exo-C=C bond isvery high. The carbon-halogen bond in the exo-C=Cbond may further be elaborated to prepare differentlysubstituted cyclic products with a stereodefined C=C bond.