Rh2(OAc)4-catalysed cycloaddition of ethyl diazoacetate to 1,2-dialkoxybenzenes: a new type of stable norcaradiene

Abstract

Rh2(OAc)4-catalysed cycloaddition of ethyl diazoacetate (EDA) to 1,2-methylenedioxybenzene 1 gives the corresponding cycloheptatrienes 6 and 7, whereas the reaction of 1,2-dimethoxybenzene 3 affords a new type of stable norcaradiene 9.