Synthesis and Structure of Carbodicarbenes and Their Application in Catalysis

Abstract

Carbodicarbenes are a special class of bisylidic CL2 compounds, the so-called carbones. Carbones are divalent carbon compounds, in which a four-electron carbon atom in the oxidation state of zero is bound by two sigma-donor ligands L via donor-acceptor interactions, resulting in the formulation L -> C(0)<- L. In carbodicarbenes (CDCs), the L ligand is a N-heterocyclic carbene (NHC) or any other singlet carbene species. Comparable to "classical" bisylides, CDCs possess two lone pairs of electrons at the central carbon atom, thus making them stronger sigma-donors than conventional carbenes like NHCs. These unusual donor properties make CDCs unique and highly potent ligands for transition metals and catalysis. This chapter summarizes the exciting developments of the last 10 years in CDC chemistry. A concise overview of this new class of carbone compounds is given by summarizing the synthesis of different CDC frameworks as well as their application in transition metal chemistry and homogenous catalysis.