Olefin insertions metal-hydrocarbyl

Insertions of Olefins into Metal-Hydrocarbyl cr-Bonds... 

Many additional routes to metal-alkyl complexes other than transmetallation and alkylation are discussed in later chapters of this text. For example, metal-alkyl complexes are generated by insertion of an olefin into a metal-hydride or or metal-hydrocarbyl species. Such insertion reactions are discussed in Chapter 9, but an example of the synthesis of a zirconium alkyl by olefin insertion into a zirconium hydride is shown in Equation 3.9. Metal-alkyl complexes are also generated by nucleophilic attack on coordinated olefins (Equation 3.10) or carbene ligands (Equation 3.11). These reactions are presented in detail in Chapter 11. 

The insertions of alk5mes into metal-carbon o-bonds are less common than either the insertions of olefins into metal-carbon bonds or the insertions of alkynes into metal-hydride bonds. Nevertheless, several examples of this reaction have been studied, and many examples are part of catalytic processes. Most of the insertions of alkynes into metal-carbon bonds occur by concerted migratory insertion pathivays and provide products from cis addition of the metal and hydrocarbyl group across the carbon-carbon multiple bond, as predicted on theoretical groimds by Thom and Hoffmann. In some cases, the products from trans addition are observed, but these kinetic products are thought to result from isomerization of the vinyl group in reaction intermediates formed by cis addition. 

The most common insertion reactions involve the insertions of carbon monoxide into metal-hydrocarbyl ligands and the insertions of olefins and alkynes into metal-hydride... 

Simpler p-halide eliminations occur from late transition metal catalysts for olefin polymerization (Equations 10.25 and 10.26). Reactions of the cationic palladium-alkyl complexes occur in a similar fashion to the reactions of the cationic group 4 complexes, despite the softer nature of these species. In this case, propylene and the metal chloride are formed. Even a neutral nickel-hydrocarbyl complex (the salicaldimine complex in Equation 10.26) undergoes reactions with vinyl chloride that involve insertion followed by P-chloride elimination. 

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