Synthesis of a Series of 4H-Pyran Derivatives with Multicomponent Reaction in DBSA/H₂O Microemulsion System

A series of 4H-pyran derivatives were synthesized through a three-component condensation reaction in a pot using aromatic aldehyde, cyclohexanedione, and malononitrile in the dodecyl benzenesulfonic acid/H₂O microemulsion system. This protocol is attractive because dodecyl benzenesulfonic acid microemulsion is superior for organic reaction due to its dual catalysis. On the one hand, dodecyl benzenesulfonic acid acts as a Brønsted acid to catalyze the reaction; on the other hand, it can form a microemulsion as surfactant to enlarge the boundary area and entrap water produced during esterification reaction. In addition, the reaction process is simple, with high liaison formation effciency, good yields, and environmentally harmless reaction conditions. The dodecyl benzenesulfonic acid/H₂O microemulsion system was equally effective when used in consecutive reactions.

Keywords:
4H-pyran; dodecyl benzenesulfonic acid; green chemistry