Multicomponent synthesis of dihydrobenzoxazepinones by coupling Ugi and Mitsunobu reactions

Abstract

Various dihydrobenzo[f][1,4]oxazepin-5-ones have been convergently prepared in 2–3 steps by coupling Ugi and Mitsunobu reactions. Two alternative methodologies were used: in the first one the Ugi condensation was followed by a Mitsunobu cyclization (2 steps); in the second one an intermolecular Mitsunobu reaction was followed by a deprotection step and then by an intramolecular Ugi reaction. Also a “convertible” isocyanide was used.