Development of New Indole-Based <i>N</i>-Heterocyclic Carbene Copper Complexes and Their Applications in Catalysis

This study disclosed the synthesis and characterization of a series of copper <i>N</i>-heterocyclic carbene (NHC) complexes incorporating an indole skeleton. Among these complexes, the Cu-NHC complex with a <i>p</i>-methoxyphenyl group on the indole ring exhibited stability in air for up to six months. In contrast, Cu-NHC complexes bearing alkyl groups on the indole ring were stable under a nitrogen atmosphere for one month. These newly developed Cu-NHC complexes proved effective as catalysts for hydrosilylation of carbonyls in 0.5 mol % loading and <i>N</i>-arylation of oxazolidinones and amides with aryl iodides in 8 mol % loading.