Recent Trends of Chromene Syntheses

Abstract

2H/4H-chromenes (2H/4H-Ch) structural scaffolds have been widely employed in the synthesis of many natural products and medicinal agents. 2H/4H-Ch have attracted considerable attention due to their various pharmacological activities, such as anticonvulsant, anticholinesterase, anticancer, anti-tuberculosis, antimicrobial, and inhibitory activity against monoamine oxidase (MAO), and anti-diabetic activities. In literature, the synthesis of 4H-chromenes was performed by one-pot Knoevenagel condensation of resorcinol, aryl aldehydes, and malononitrile in the presence of basic catalysts. Also, 2H-Ch analogs were performed by the Wittig-Horner-Emmons and Suzuki-Miyaura cross-coupling reactions. A description of recent advances in the syntheses of chromenes is presented in this chapter. The strategies for the synthesis of 2H/4H-Ch discussed in this chapter are organocatalysts, organometallic or metal catalysts, heterogeneous base catalysts, enzymatic catalysts, and green chemistry-based approaches.