Transition metal organometallic synthesis reagents

Allan J. Canty, Thomas Rodemann, and John H. Ryan, Transition Metal Organometallic Synthesis Utilising Diorganoiodine(HI) Reagents. . . Al-Ahmad, Saleem, see Ashe, Arthur J., HI... 

Organomercurials are useful reagents for the synthesis of other organometallic complexes. Direct transmetallation is the most common approach and a large number of main group and transition metal organometallic complexes have been prepared in this way from organomercurials. 

See, for example. Transition Metal Organometallics in Organic Synthesis, Vols. I and II, H. Alper, Ed., Academic, New York, 1976 G. H. Posner, An Introduction to Synthesis using Organocopper Reagents, Wiley-Interscience, New York, 1980. 

For a review of counterattack reagents, see Hwu, J.R. Gilbert, B.A. Tetrahedron 1989, 45, 1233. For a monograph that discusses most of the reactions in this section, see Stowell, J.C. Carbanions in Organic Synthesis, Wiley, NY, 1979. For a review, see Noyori, R., in Alper, H. Transition Metal Organometallics in Organic Synthesis, Vol. 1, Academic Press, NY, 1976, pp. 83-187. 

Main-group examples of C-H activation, such as arene mercuration, are long known, but tend to involve stoichiometric reagents, not catalysts, and many use metals that are now avoided on toxicity grounds (Hg, Tl, and Pb). Catalytic reactions involving transition metal organometallic activation and functionalization of C-H bonds (Section 12.4) are beginning to move into the applications phase and are likely to become much more common in synthesis." " Innate selectivity can sometimes permit functionalization of one out of the many... 

In this section, selected examples of syntheses of insect defensive compounds will be presented. The impact of asymmetric synthesis and the increasing use of organometallic reagents, notably transition metal catalysts, will be highlighted. 

The synthesis of functionalized zinc organometallics can be accomplished with a variety of methods that have been developed in recent years. The intrinsic moderate reactivity of organozinc reagents can be dramatically increased by the use of the appropriate transition metal catalyst or Lewis acid. Furthermore, the low ionic character of the carbon-zinc bond allows the preparation of a variety of chiral zinc organometallics with synthetically useful configurational stability. These properties make organozinc compounds ideal inteimediates for the synthesis of complex and polyfunctionalized organic molecules. 

It is an axiom of modern organometallic chemistry that the pursuit of late transition metal complexes is ultimately driven by the need to formulate ever more efficient catalysts and reagents for chemical synthesis. In this respect, the field of poly(pyrazolyl)borate chemistry is no different from any other, albeit that in the case of the group 10 triad the breadth of study is perhaps more limited than for other metals and/or ligands. This section provides an overview of prominent results in respect of both catalysis and the C—H activation processes that underpin them. 

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