Rearrangement reactions of bicyclic systems. Part I. Synthesis of a model compound related to flavothebaone trimethyl ether. The abnormal ultraviolet absorption spectrum of flavothebaone and its trimethyl ether

Abstract

3,6-Dimethoxybenzenediazonium-2-carboxylate decomposed to 3,6-dimethoxybenzyne (8), which reacted with veratrole to form 1,5,8-trimethoxy-1.4-etheno-2-tetralone (9) in 40% yield. Reduction, and acid-catalysed rearrangement of the resulting exo-alcohol (10). afforded 5,9-dihydro-1,4-dimethoxy-5,9-methanobenzocyclo-hepten-6-one (7). The u.v. spectrum of compound (7) is entirely analogous to that of flavothebaone trimethyl ether (3).