Indol‐2‐ylidene (IdY): Ambiphilic N‐Heterocyclic Carbene Derived from Indole

The synthesis of ambiphilic N‐heterocyclic carbene ligand, indol‐2‐ylidene (IdY, A), is described. A series of indolenium precursors (2 a–f) were prepared on a gram scale in good yields. Trapping experiments with elemental selenium, [RhCl(cod)]2 and CuCl provided the expected carbene adducts. Further computational and spectroscopic studies supported the ambiphilicity of IdY, which lies between cyclic (alkyl)(amino)carbenes (CAAC‐5) and cyclic (amino)(aryl)carbene (CAArC). The copper complexes (6) show high percent buried volume (% Vbur = 58.1) and allow for carboboration of terminal alkynes within 30 minutes in a demonstration of synthetic utility with good yields and high regioselectivity. Ambiphilic N‐heterocyclic carbene, indol‐2‐ylidene (IdY), is reported. The ambiphilicity is characterized by IdY‐supported materials. The nonclassical hydrogen bonding (NCHB) of IdY–Se complex is characterized by X‐ray and computational studies. Furthermore, the carboboration of terminal alkynes using IdY–Cu complexes can be performed within 30 minutes with good yields and high regioselectivity.