Metallaphotoredox-catalyzed alkynylcarboxylation of alkenes with CO₂ and alkynes for expedient access to β-alkynyl acids.

Abstract

Carboxylation with CO₂ offers an attractive and sustainable access to valuable carboxylic acids. Among these methods, direct C-H carboxylation of terminal alkynes with CO₂ has attracted much attention for one-carbon homologation of alkynes, enabling rapid synthesis of propiolic acids. In contrast, the multi-carbons homologation of alkynes with CO₂ to construct important non-conjugated alkynyl-containing acids has not been reported. Herein, we present alkynylcarboxylation of alkenes with CO₂ via photoredox and copper dual catalysis. This protocol provides a direct and practical method to form valuable non-conjugated alkynyl acids from readily available alkynes, alkenes and CO₂. Additionally, this approach also features mild (room temperature, 1 atm of CO₂) and redox-neutral conditions, high atom and step economy, good functional group tolerance, and high selectivities. Moreover, diverse transformations of the β-alkynyl acid products and the rapid synthesis of bioactive molecule (GPR40/FFA1 agonist) further illustrate the synthetic utility of this methodology.