A new synthesis of oxazoles by an intramolecular aza-Wittig reaction is described. Readily available a-azido ketones 2 were converted to (Z)-P-(acyloxy) vinyl azides 3 by selective enol acylation. These vinyl azides 3 reacted with triethyl phosphite to afford the corresponding oxazole derivatives 5 via the Staudinger reaction, followed by an intramolecular aza-Wittig reaction. In particular, this oxazole synthesis was useful for ...