A series of two-coordinate copper tert-butoxide complexes bearing five-, six-, and seven-membered ring N-heterocyclic carbenes, prepared by protonolysis of (NHC)CuMes with tBuOH, have been used as catalytic precursors in the semihydrogenation of alkynes with silanes/tBuOH and the hydroboration of alkynes with HBPin. Both processes proceed with high regioselectivity and show enhancements with six- and seven-membered ring carbenes.
Hall, J., Unson, D., Brunel, P., Collins, L., Cybulski, M., Mahon, M., & Whittlesey, M. (2018). Copper-NHC-Mediated Semi-Hydrogenation and Hydroboration of Alkynes: Enhanced Catalytic Activity Using Ring-Expanded Carbenes. Organometallics, 37(18), 3102-3110. https://doi.org/10.1021/acs.organomet.8b00467