Regioselective synthesis of distal-bisalkoxytetrathiacalix[4]arenes by a protection–deprotection method using benzyl groups

Regioselective synthesis of distal-bisalkoxytetrathiacalix[4]arenes is accomplished by a protection–deprotection method using benzyl groups as a protecting group. The deprotection of benzyl group was succeeded in the presence of AlCl 3 or solid superacid (Nafion-H) under refluxing benzene.