Here, we describe mechanistic studies of the retro-Diels-Alder reaction of 4 H-1, 2- benzoxazines bearing various substituents on the benzene ring. 4 H-1, 2-Benzoxazines are very simple, but quite new, heterocyclic compounds that afford substituted o-quinone methides (o-QMs) through retro-Diels-Alder reaction under mild thermal conditions. The resultant o-QMs undergo Diels-Alder reaction in situ with dienophiles to give phenol and ...
