Carbon orthometallated

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). 

Good yields of l-arylaminoquinolin-2-ones are obtained when the azo-arene complexes 116 are treated with hexafluorobut-2-yne (Scheme 141).214 This procedure is particularly novel in the chemistry of orthometallated complexes in that the primary organometallic products (117) arise from the formal insertion of a three carbon unit [CO + C2(CF3)2] into the aryl-cobalt bond of 116. A wider study of the scope of this type of process using a variety of orthometallated complexes would be desirable. 

Several chapters deal with the synthesis of and the synthetic applications of organolithium compounds such as orthometallation, arene catalysed lithiation, addition to carbon-carbon double bonds, their reaction with oxiranes, and asymmetric deprotonation with lithium (-)-sparteine. We gratefully acknowledge the contributions of ah the authors of these chapters. 

The metallation of -hybridized carbon atoms is more facile than that of sp3-C the reaction of phenyl rings is known as orthometallation. Some... 

These are reactions that incorporate metals into organic rings. The most common of these are orthometallations, oxidative additions in which the ortho position of an aromatic ling becomes attached to the metal. The first example in Figure 14-4 is an OA in which an ortho carbon and the hydrogen originally in the ortho position add to iridium. 

This reaction is also called orthometallation because it is the ortho carbon of the phenyl group that participates. Although most common with phenyl groups of phosphines or phosphites, examples involving alkyl groups are also known. 

Even a carbon-carbon double bond is capable of facilitating orthometallation when a halogen group is being replaced. 

The cyclometallation reaction in which the metallated carbon is aliphatic occurs less frequently than does the aromatic carbon reaction (orthometallation) (see 5.8.2.6.4). 

FIGURE 14.5 Cyclometallation Reactions. The first reaction is an orthometallation where the iridium coordinates to the carbon ortho to the phosphorus atom. 

The various kinds of 2-ferrocene derivatives are synthesized by reaction with transition metal compounds in a manner similar to the orthometalation of phenyl compounds. The palladium compounds 7.54 of dimethylaminomethylferrocene react with carbon monoxide in methyl alcohol to give the 2-methoxycarbonyl compound 7.45, and subsequent treatment of the product with methyl iodide, sodium amalgam, and phosphoric acid gives l-methyl-2-carboxylic acid 7.55. Reduction of the 2-methoxycarbonyl compound 7.45, followed by treatment with NaOH, produces an alcohol 7.56, and oxidation of the compound 7.56 yields an aldehyde 7.57, as shown in Scheme 7.9. Since the starting material 7.54 is an optically active compound, as shown in Scheme 7.9, all of its derivatives are also optically active 1,2-ferrocene derivatives [68]. 

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