Discussion Addendum for: Convenient Preparation of 3‐Ethoxycarbonyl Benzofurans from Salicylaldehydes and Ethyl Diazoacetate

Abstract

The benzofuran scaffold is an important heterocyclic core component found in several natural products and in polymers. Typically, 2,3‐disubstituted benzofurans are notable building blocks in many medicinal and biologically active compounds. In addition, 3‐substituted benzofurans act as anticancer agents, antitubercular agents, antimicrobial agents, antiviral agents, and anti‐inflammatory agents. This addendum discusses the preparation of 3‐ethoxycarbonyl benzofurans from salicylaldehydes and ethyl diazoacetate. It presents alternate methods to prepare 3‐alkoxycarbonyl benzofurans through four schemes: synthesis by a thallium catalyzed oxidation annulation, synthesis by a palladium‐catalyzed cyclization, synthesis by a palladium assisted CO insertion, and synthesis by a copper‐catalyzed cyclization. The addendum also provides information on the applications of the one‐pot synthetic method that has been used by the authors and by other groups in the preparation of several biologically active compounds in organic synthesis.