Die Stereochemie der fragmentierenden Enthalogenierung von 1-Chlor-1-fluor-2-(1-halogenalkylcyclopropanen

Article abstract of DOI:10.1002/hlca.19800630516

A number of a model substrates were submitted to zinc-promoted fragmentation, and the composition of the resulting mixture of isomeric fluorodienes was determined.The exocyclic reaction center, bearing the electrofugal leaving group, was found to undergo almost complete stereochemical randomization in the course of the reaction.On the oher hand, the ring-opening proceeds stereoselectively.The rotation, which brings the substituents of the halogen-free ring position into the plane of the new, fluorine-bearing double-bond, occurs mainly in that sense to move the electrons of the breaking ring linkage into the rear of the departing chlorine atom.