STEREOSPECIFIC CYCLOADDITION OF HETEROCUMULENES TO OXIRANES CATALYZED BY ORGANOTIN HALIDE-COMPLEXES

Stereospecific cycloaddition of 2,3-disubstituted oxiranes to heterocumulenes, including carbodiimides, isocyanates and carbon dioxide, is catalytically promoted by dialkyltin diiodide-hexamethylphosphoric triamide (HMPA) system, producing various five-membered heterocycles, where the configuration of the carbons in the oxirane ring is retained. In particular, the addition of isocyanates to oxiranes gave stereo-specifically two types of products, dioxolan-2-imines and oxazolidin-2-ones independently, while the rearrangement of the former to the latter product has been already proposed.