Silica-supported boric acid with ionic liquid: a novel recyclable catalytic system for one-pot three-component Mannich reaction.

A rapid and efficient silica-supported boric acid/ionic liquid ([bmim][PF₆]), catalyzed, one-pot three-component Mannich reaction has been carried out to synthesize β-amino carbonyl compounds at room temperature. The reaction afforded desired products in excellent yields with moderate to good diastereoselectivity. The method provides a novel modification of three-component Mannich reaction in terms of mild reaction conditions, clean reaction profiles, low amount of catalyst, recyclability of catalyst and a simple workup procedure. The present report first time describes the preparation of H₃BO₃-SiO₃ catalyst and its use with [bmim][PF₆], to synthesize Mannich products. The catalyst can be reused at least seven times.