Hammet Constants Effects in Microwave Cascade Etherification-Cyclization-Krapcho Reaction to Access [2,3]-Dihydrobenzofuran-3-ones from Salicylic Derivatives

Abstract

Two methods were evaluated for the synthesis of substituted [2,3]-dihydro-2-methyl-benzofuran-3-ones from corresponding salicylate esters under microwave irradiation. A two-step sequence via ether intermediates was convenient for various substituted salicylate derivatives, while the second strategy involving a one-pot procedure was efficient for electron-donating substituted salicylates. Results allowed correlation of the Hammett constants effects in the intramolecular cyclization of O-ethoxycarbonyl ether of salicylic esters.