Functionalization of oxabenzonorbornadiene: Manganese(III)-mediated oxidative addition of dimedone

Abstract

3-Chloro-1,2,3,4-tetrahydro-1,4-epoxynaphthalen-2-yl)-3-hydroxy-5,5-dimethylcyclohex-2-en-1-one, synthesized by the reaction of oxabenzonorbornadiene with Mn(OAc)3 and dimedone in the presence of HCl in acetic acid, was submitted to ring-opening reactions with BBr3 and H2SO4. Reaction with BBr3 yielded 2 products, a 5-membered ring and an 8-membered ring, with the former being the major product. However, the H2SO4-supported reaction exclusively formed an 8-membered ring. The mechanism of formation of these products was supported by theoretical calculations.