A Facile and Convenient Synthesis of Chromenes using Reusable Sulfonic Acid Functionalized Imidazolium Salt

Abstract

An efficient synthesis of chromene derivatives was realized by the condensation of phenols and acetophenones using a reusable sulfonic acid-functionalized imidazolium salt as catalyst. The catalytic system has wide substrate scope and provided good to excellent yield of chromenes. Interestingly, the system was easily recycled and was also suitable for a gram scale synthesis of chromene. The mild reaction conditions, absence of metal catalyst and recyclability of catalyst used makes this protocol more attractive for the synthesis of potentially bioactive compounds. The method avoids the disposal and neutralization of acidic catalyst.