Organometallic compounds contain a carbon-metal bond

Organometallic compounds contain a carbon-metal bond 

CHAPTER 9 USING ORGANOMETALLIC REAGENTS TO MAKE C-C BONDS 

You have already met cyanide (p. 121), a carbanion that really does have a lone pair on carbon. Cyanide s lone pair is stabilized by being in a lower-energy sp orbital (rather than sp3) and by having the electronegative nitrogen atom triply bonded to the carbon. 

We can also say that, because the carbon s sp orbital makes a greater contribution to the C—Li c bond, the a bond is close in structure to a filled C sp orbital—a lone pair on carbon. This useful idea can be carried too far methyl lithium is not an ionic compound Me Li — although you may sometimes see MeLi or MeMgCl represented in mechanisms as Me . 

It turns out that they generally form complex aggregates with two, four, six, or more molecules bonded together, often with solvent molecules, one reason why apparently polar compounds such as BuLi dissolve in hydrocarbons. In this book we shall not be concerned with these details and we shall represent organometallic compounds as simple monomeric structures. 

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Organometallic compounds contain a carbon-metal bond They are named as alkyl (or aryl) derivatives of metals... 

ORGANOMETALLIC COMPOUNDS CONTAIN A CARBON-METAL BOND... 

Organometallic compound A compound containing a carbon—metal bond. 

Organometallic compounds which contain a carbon-metal bond are the most reactive carbon nucleophiles. In most cases they are also powerful bases and must be prepared and used under strictly anhydrous and aprotic conditions. A very common way to produce organometallic compounds is to reduce alkyl halides with active metals. Grignard reagents and organolithium compounds are routinely produced in this manner. The transformation is a two-electron reduction of the alkyl halide to a carbanion equivalent the metal is oxidized. 

The term organometallic refer to compounds that contain a carbon-metal bond. [59] The term spans compounds that are primarily ionic (such as when the metal is sodium or potassium and thus should be nomenclated as the distinct ions) through compounds that are primarily covalent (such as when the metal is lead, tin, mercury or thallium for which the bonding is covalent)... 

The reactions between C-H compounds and metal complexes in a low oxidation state, which produce organometallic derivatives (i.e., compounds containing direct carbon-metal bonds) will be considered in this chapter, hi some cases the intermediate o-organyl and organyl hydride complexes can not be isolated, although the evidence for their formation is obtained. Reactions of such type (often-catalytic processes) will be considered in this chapter. 

In this Chspter, we undertake our first discussion of a broad class of organic compounds called organometallic compounds, compounds that contain a carbon-metal bond. In recent years, there has been an enormous explosion in our understanding of their chemistry, particularly as stereospecific (and often enantioselective) reagents for synthetic chemistry. We have already seen one example in the Sharpless enantioselective epoxidation of alkenes (Section 11.8D). 

An organometallic compound is one that contains a carbon-metal bond. 

Organometallic compound (Section 12.4) A compound that contains a carbon—metal bond. Grignard reagents, RMgX, are examples. 

Because metals are less electronegative than carbon (Table 12.1), one way to create a nucleophilic carbon is to attach the carbon to a metal. A compound that contains a carbon-metal bond is called an organometallic compound. The electrostatic potential maps show that the carbon attached to the halogen in the alkyl halide is an electrophile (it is blue-green), whereas the carbon attached to the metal (Li) in the organometallic compound is a nucleophile (it is red). 

There are distinct structural types of organic compounds containing metals and metalloids. The first contain covalent carbon-metal bonds and are strictly organometallic compounds, for example, the alkylated compounds of Hg, Sn and Pb, and of Li, Mg, and A1 (and formerly Hg), which have been extensively used in laboratory organic synthesis, and A1(C2H5)3 that is a component of the... 

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