The Reaction of Anhydrochloralurethanes with Ketene Acetals

The reaction of anhydrochloralurethanes (I) with ketene acetals (II) has been found to give novel carbamate derivatives (III) in quantitative yield. The intermediacy of a cyclic intermediate, an oxazine derivative (IV), was confirmed by spectroscopic methods, although several attempts to isolate IV have been unsuccessful. The mechanism for formation of IV is discussed.