Electrochemical Controllable Divergent Carboxylation and Hydrocarboxylation of Alkynes with CO2.

Carboxylation and hydrocarboxylation of alkynes with CO2 for the synthesis of value-added and versatile carboxylic acids are of great importance. However, harsh reaction conditions, poor selectivity, practicability, and sustainability have always restricted its application. Electrochemical synthesis has been considered as a practical and environmentally friendly organic synthesis strategy via a tunable redox process. Hence, herein, an efficient electrochemical controllable divergent carboxylation and hydrocarboxylation of alkynes with CO2 was achieved to overcome the limitation of traditional methods. Four kinds of arylpropiolic acid, cinnamic acid, fumaric acid, succinic acid, and their derivatives can be obtained with good selectivity by regulating substrates, solvents, and electrolytes. The method features broad substrate scope, divergent transformation with good selectivity, scalability, additional reducing agent-, hydrogen donor-, metal-, and ligand-free conditions, which offer novel insights into electrochemically driven CO2 fixation and alkyne functionalization.