Visible Light Promoted Iron-Catalyzed One-Pot Synthesis of 2-Arylimino-2H-Chromenes from 2-Hydroxybenzyl Alcohols and β- Ketothioamides at Room Temperature

Abstract

An efficient, environmentally benign and one-pot approach for the synthesis of 2-arylimino-2H-chromenes from 2-hydroxybenzyl alcohols and β-ketothioamides at room temperature under visible light has been developed. The reported reaction conditions were favorable for a wide range of β-ketothioamides afforded good to excellent yields of the respective products. The low cost and air stable Knölker iron catalyst has been employed for the dehydrogenation of 2-hydroxybenzyl alcohols under photolysis that would usually require a higher temperature.