Cyanoalkyl complexes

It has been shown that the addition of HCN to the alkene occurs in a cis (suprafacial) manner.601 This was achieved by the addition of DCN to (E)- -deuterio-3,3-dimethylbut-l-ene, catalyzed by [Ni P(OPh)3 4] (131) (equation 162). This requires retention of configuration at the alkyl carbon atom during the reductive elimination of the product from the intermediate nickel(II)-alkyl complex. A cyanoalkyl complex [Ni(CN)(CHDCHBut) P(OPh)3 2] was proposed as the key intermediate in this process. 

Similarly, the cyanoalkyl complexes, 7.6, on treatment with acids, form cations for which jc-keteneimine structures are proposed [10]. 

Kwiatek and Seyler were the first to report that many organopenta-cyanides, when treated first with acid and then with alkali, liberate nitriles 110). This reaction occurs with unsubstituted primary and secondary alkyl, benzyl, vinyl, and phenyl complexes, while allyl, 2-oxo-, 2-hydroxy-, and 2-alkoxy complexes simply release the organo-ligand on treatment with acid, and 1-cyanoalkyl and a-pyridyl complexes are stable 105) (see also Table IV). The yield of nitrile is usually far from quantitative and is... 

Titanium chelates of semi-salen 59 and salen 60 are used in asymmetric synthesis of a-cyanoalkyl ethyl carbonates from aldehydes and ethyl cyanoformate. By changing the metal atom to aluminum for complexing 60 a catalyst for elaborating a-acetoxy amides (Passerini reaction) is obtained (but enantioselectivity varies)/ ... 

A similar case occurs with cyanoalkyls, which may be reversibly protonated to ketene imine complexes ... 

Figure 25 General mechanism of the reaction of cyanoalkyl radicals with metal complexes and olefin monomers.

The cyanoalkyl py3RhCl2(CHMeCN) is formed by addition of pyridine and acrylonitrile to RhCh in ethanol [48c]. Possibly a Rh-hydride intermediate is involved in this reaction. The unusual methyl complexes (Ph3P)2MMeClI(MeI), where M = Rh or Ir, are of interest since they are thought to contain Mel acting as a ligand to the metal via the iodine [48d]. If it does then these are the first examples where an alkyl halide complexes with a transition metal. 

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