Orthometalation aromatic compounds

Aromatic compounds with side-chain sulfur donors orthometallate when the sulfur is in a thioketone , thiobenzoate ester or a thioether group . In the thioethers an additional coordinating group is required to achieve orthometallation ... 

Great number of publications has been devoted to cyclometalation, especially to the reactions with C-H bonds of aromatic compounds (orthometalation) [3] which proceed according to the general equation ... 

Electrophilic Addition to Aromatics. Aromatic compounds are fluorinated with 1 by heating without a solvent to about 100-150 °C, or, for low-boiUng compounds, up to reflux temperature. Activated aromatics, such as anlsole or N-acetylaniline, react smoothly, whereas toluene requires considerably longer reaction times and gives low yields (eqs 9 11). In all cases, the regioselectivities are consistent with an electrophilic addition mechanism ortho- and para-substituted products predominate over the meta-isomers. 1 has recently been used in orthometalation-directed fluorination of aromatics. ... 

It is interesting to notice that the complex 58 is also able to react with soft donor hgands such as triphenylphosphine resulting in the formation in very mild conditions of the unexpected orthometallated complex 59 (Scheme 23) [89,91, 92]. The ligand here is linked to the metal through both an aromatic and an ylidic carbon. Other transformations are realized from 58 leading, including the compounds of the previous scheme, to four different structures for the bis-ylide (i) C,C-chelate (ii) C,C-orthometallated (iii) C,C-orthometallated and free ylide (iv) C,C,C-terdentate (Scheme 23). 

A detailed analysis (113) demonstrated that oxidation of [Ir (Cp )-Me2(PPh3)] initially yields the orthometalated product [Ir° Cp )Me(K -RC- —C5H4(Ph)2p )], which could be prepared as a pure compound in CH2CI2. In the presence of aromatic solvents and a catalytic amount of an oxidant, the latter converts to [Ir (Cp )Me(Ar)(PPh3)]. The outcome of the reactions is independent of the use of either Ag or Fc as the chemical redox catalyst. A small, but... 

As shown in eq. (3.11), if a hetero atom such as nitrogen, sulfur or oxygen is located at the / -position of the aromatic ring, the lithium metal at first is coordinated by the hetero atom and activated, and then it forms a stable five-membered ring by electrophilic attack at the ortho carbon. The five-membered ring formation reaction as shown in eq. (3.11), proceeds easily not only with lithium but also with the many other metals. This reaction is called orthometalation or cyclometalation [30]. For example, the five-membered ring compounds are produced by reaction of dimethylaminomethybenzene with alkyllithium as shown in eq. (3.12) [31-33]. Similar reactions are known on the compounds of metals such as Si, Sn, Hg, Mn, Cu, Ni, Cr, Co, Pt, Pd, Rh, Ti, V, Sc, Y, La, Nd and Er. [30]. 

A novel meridional bicyclometallation was achieved by methane extrusion from [Fe(CH3)2(PMe3)4] with A -benzylidene-l-naphthylamine and (l-naphthyl)(2-pyridyl)ethene. In the crystal structures of isomeric 131 and 132, the iron center bears three meridional PMe3 ligands. C-H activation of aromatic imines in the presence of [Fe(CH3)2(PMe3)4] or [Fe(PMe3)4] led to the orthometallated methyl and hydride compounds 133 and 134, respectively. ... 

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