REARRANGEMENTS OF SUBSTITUTED 3-AZIDOAZETIDINES - UNEXPECTED FORMATION OF A SUBSTITUTED OXAZOLE

Thermolysis of neat N-carboethoxy-3-azido-3-ethylazetidine (3) at 200 degrees under argon produced the corresponding cyclic imine 4 (68% yie ld). Prolonged refluxing of a mixture of N-triflylazetidin-3-one (7), sodium azide, and titanium tetrachloride in acetonitrile solvent affor ded recovered 7 (25% yield) along with a colorless microcrystalline so lid, 8, mp 104-105 degrees (20% yield), whose structure was establishe d unequivocally via application of X-ray crystallographic methods.