Dicationic ionic liquids as recyclable catalysts for one‐pot solvent‐free synthesis of α‐aminophosphonates

Some task‐specific ionic liquids N , N , N ′, N ′‐tetramethyl‐ N , N ′‐dipropanesulfonic acid ethylene‐diammonium hydrogen sulfate, N , N , N ′, N ′‐tetramethyl‐ N , N ′‐dipropanesulfonic acid‐1,3‐propanediammonium hydrogen sulfate, N , N , N ′, N ′‐ tetramethyl‐ N , N ′‐ dipropanesulfonic acid‐1,6‐hexanediammonium hydrogen sulfate were prepared. These ionic liquids could be used as efficient and recyclable catalysts for the synthesis of α‐aminophosphonates at room temperature via an one‐pot three‐component reaction under organic solvent‐free conditions with good yields of 83–96%. The postprocessing was simple, and the catalysts could be reused at least six times without noticeably decreasing the catalytic activity. The novel clean procedure offers the advantages including short reaction time, good yields, operational simplicity, and environmentally benign.