Debenzylation of Aryl Benzyl Ethers by Using Solid-Supported Acids

Significance

Amberlyst-15-mediated aromatic debenzylation reactions are described. The debenzylation of vanillin benzyl ester 2 (R¹ = Me, R² = Bn, X = CHO) using a stoichiometric amount of Amberlyst-15 (a sulfonic acid on polymer support) 1 was performed in toluene at 110 °C with 4 equiv­alents of methanol for two hours to give vanillin 3 (R³ = Me, R⁴ = H, X = CHO) in 98% yield. The conditions are also compatible with functional groups such as nitrostyrene (X = HC=CHNO₂) which is susceptible to hydrogenation and/or reduction conditions. The procedure is simple as it requires only filtration to remove the polymer from the reaction mixture.