Synthesis of chlorinated bicyclic C-fused tetrahydrofuro[3,2-c]azetidin-2-ones

Bicyclic C-fused chlorinated tetrahydrofuro[3,2-c]azetidin-2-ones are prepared by a general route involving Staudinger reaction of allylic/propargylic imidates with dichloroketene followed by highly diastereoselective CuCl/PMDETA-catalyzed 5-exo-trig/dig chlorine atom transfer radical cyclization. Synthetic application of the side chain chlorine atom of the products is shown by its substitution in one of the products with azide followed by azide-alkyne click reaction with phenylacetylene to obtain a 1,2,3-triazolyltetrahydrofuro[3,2-c]azetidin-2-one.