Bicyclic (Alkyl)(amino)carbenes (BICAACs): Stable Carbenes More Ambiphilic than CAACs

A straightforward strategy allows for the synthesis of storable bicyclic (alkyl)(amino)carbenes (BICAACs), which feature enhanced sigma-donating and pi-accepting properties compared to monocyclic (alkyl)(amino)carbenes (CAACs). Due to the bicyclo [2.2.2]-octane skeleton, the steric environment around the carbene center is different from that of CAACs and similar to that observed in classical N-heterocyclic carbenes. The different electronic properties of BICAACs as compared to CAACs allow for ligand exchange reactions not only at a metal center, but also at main group elements.