Inserting CO2 into Terminal Alkynes via Bis-(NHC)-Metal Complexes

The direct interaction between CO 2 and terminal alkynes in the presence of bis-(NHC)-metal catalysts at ambient conditions was studied. Two Cu and Ag-based bis- N -heterocyclic carbene Transition Metal catalysts were synthesized. The (NHC) 2 -Ag complex showed a better catalytic performance towards the carboxylation of terminal alkynes in comparison with the copper analogue even for the conversion of acetylene gas. The optimized conditions for the carboxylation are: the use of Cs 2 CO 3 as additive, one atmosphere CO 2 and room temperature using 1% mol catalyst. Mechanistic insight into the reaction mechanism is obtained by means of state-of-the-art first principles calculations. Graphical Abstract