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.
Keywords: 2H/4H-chromenes, Enzymatic catalyst, Green chemistry approaches, Heterogeneous base catalyst, Knoevenagel condensation, Organo-base-catalyst, Pharmacological activities, Wittig-Horner-Emmons.
