Carbodicarbenes

Lewis Acid Activation of Carbodicarbene Catalysts for Rh-Catalyzed Hydroarylation of Dienes

“…Divalent carbon(0) compounds, such as CDCs and carbodiphosphoranes (CDPs), represent an emerging area in ligand development for transition-metal catalysis and provide strategies to access new modes of reactivity . Principal to their reactivity is a divalent carbon(0) supported by two L-type donor groups . Unlike their carbon­(II) analogs, N-heterocyclic carbenes (NHCs), the reactivity profile of carbon(0) ligands is centered around two lone-pairs of electrons that are available for binding to Lewis acids.…”

Intermolecular Hydroamination of 1,3-Dienes Catalyzed by Bis(phosphine)carbodicarbene–Rhodium Complexes

“…Accordingly, the development of new classes of carbon-based ligands for use in transition-metal catalysis is an important goal in chemical synthesis. Carbodicarbenes (CDCs), , also referred to as bent allenes, are a family of compounds that contain a divalent carbon(0) center, captodatively stabilized by two carbene donors. These ligands can effectively bind to transition metals, and their σ- and π-electron-donating properties have been established both experimentally and by theoretical calculations to be stronger than those of N-heterocyclic carbenes (NHCs).…”

Possibility of the Existence of Donor–Acceptor Interactions in Bis(azole)amines: An Electronic Structure Analysis

“…Recent reports on the existence of an atypical bonding situation in the (L → C ← L) systems (called carbones) with carbon in the C(0) state − are challenging the traditional notions regarding the bonding states of carbon, which is well-known to exist in C(IV) and C(II) states. Such C(0) compounds have gone through intense experimental and theoretical investigations due to their strong electron-rich character. − The pioneering work in this field therefore resulted in the establishment of unusual bonds like (L → E) in many compounds with main group element E (where E = C, − , Si, − Ge, ,, Sn, , Pb, N, , N + , − , P, , P + , , B, − As, , etc.) and L (electron-donating groups: PR 3 , , diamino carbene, N -heterocyclic carbenes (NHC), ,,,, and cyclopropenium carbene, ,…”

“…and L (electron-donating groups: PR 3 , , diamino carbene, N -heterocyclic carbenes (NHC), ,,,, and cyclopropenium carbene, , etc.). Electronic structure studies were carried out, various compounds were designed, a few compounds were newly synthesized, and a number of already existing compounds were analyzed with reference to this new perspective. − Similarly, there are several studies reporting novel bonding. Among these, the compounds with divalent N(I) character ( I – IV , Scheme ) are of special interest because many medicinally important species carry the newly identified electronic interaction (L → N). − In our previous studies, we have already discussed the existence of this unusual bonding environment in drugs like metformin (antidiabetic), famotidine (antiulcerative), ebrotidine (antiulcerative), and cycloguanil (antimalarial) .…”