Alkylation of 3,4-methylenedioxyphenol with 1-bromo-3-methylbut-2-ene and catalytic rearrangement of the resulting ethers

Abstract

Sodium and potassium 3,4-methylenedioxyphenolates have been alkylated with 1-bromo-3-methylbut-2-ene in a variety of solvents. Not only the products of O- and C-monoalkylation but also products of dialkylation have been obtained. In the C-alkylation products both 3-methylbut-2-enyl compounds and their 1,1-dimethylprop-2-enyl isomers were found. Factors which may influence the reaction course are discussed briefly. The rearrangement of 1-(3-methylbut-2-enyloxy)-3,4-methylenedioxybenzene (3) in decalin in the presence of zinc chloride gave largely 2-(3-methylbut-2-enyl)-4,5-methylenedioxyphenol (4) and 2,3-dihydro-2,2,3-trimethyl-5,6-methylene-dioxybenzofuran (11). Similarly, 1-(3-methylbut-2-enyl)-2-(3-methylbut-2-enyloxy)-4,5-methylenedioxybenzene (7) yielded the phenol (4) and 2,6-bis-(3-methylbut-2-enyl)-3,4-methylenedioxyphenol (10).