Amides Enable Room-Temperature CO2 Conversion: Simple Organic Molecules Challenging Metal Catalysts

Abstract

The conversion of carbon dioxide (CO₂) into valuable chemicals has been intensively pursued for sustainable chemistry. It is highly desirable to achieve the conversion under ambient conditions using organocatalysts instead of precious or pollutive metal catalysts. Herein, we disclose a new class of organocatalysts for direct C(sp)–H carboxylation with CO₂. Amide molecules such as N-methylacetamide and valerolactam behave as efficient bifunctional catalysts to promote the conversion of aromatic alkynes to propiolic acids. In particular, the simple organic catalysts enable the reaction to occur at room temperature, which has been achieved only with complex transition metal catalysts prior to this report. In the presence of the optimal base of Cs₂CO₃, the adjacent nitrogen and oxygen sites of the amide group concurrently activate CO₂ and C(sp)–H and position them in favor of C–C coupling, affording a high catalytic activity on par with those of transition metal catalysts. The work sheds new light on the catalytic chemistry of CO₂ and also illustrates the great potential of discovering new organocatalysts from simple molecules.