Organometallic compounds organolithium

The most general synthetic route to ketones uses the reaction of carboxylic acids (or their derivatives) or nitriles with organometallic compounds (M.J. Jorgenson, 1970). Lithium car-boxylates react with organolithium compounds to give stable gem-diolates, which are decom-... 

Before we describe the applications of organometallic reagents to organic synthesis, let us examine their preparation. Organolithium compounds and other Group I organometallic compounds are prepared by the reaction of an alkyl halide with the appropriate metal. 

Organolithium and organomagnesium compounds find their- chief use in the preparation of alcohols by reaction with aldehydes and ketones. Before discussing these reactions, let us first exanine the reactions of these organometallic compounds with proton donors. 

Organolithium and organomagnesium compounds are stable species when prepaied in suitable solvents such as diethyl ether. They aie strongly basic, however, and react instantly with proton donors even as weakly acidic as water and alcohols. A proton is transfened from the hydroxyl group to the negatively polaiized caibon of the organometallic compound to fomn a hydrocaibon. 

Organolithium reagents are also valuable in the synthesis of other organometallic compounds via... 

As with the reduction of aldehydes and ketones (16-23), the addition of organometallic compounds to these substrates can be carried out enantioselectively and diastereoselectively. Chiral secondary alcohols have been obtained with high ee values by addition to aromatic aldehydes of Grignard and organolithium compounds in the presence of optically active amino alcohols as ligands. ... 

Decarboxylation reactions of metal carboxylates [Eq. (1)], are of increasing value in the synthesis of organometallic compounds (1-5). The reverse reaction, e.g., carbonation of Grignard and organolithium reagents (6,7), is a well-known source of carboxylic acids. Early reviews of the... 

Metathesis reactions continue to be extensively employed in the synthesis of organomercury compounds. While most reactions involve the use of organolithium or Grignard reagents, other organometallic compounds are sometimes used as starting materials. 

A sample of organolithium compound solution is added to an excess of standardized iodine solution in Et20 the excess iodine is extracted with aqueous KI and titrated with standard thiosulfate solution. Evaluation of the organometallic compound is made according to equation. A possible interference can be expected from the couphng reaction in equation 20. This was shown to be neghgible, as demonstrated spectrofluorometrically for phenyllithium , whereas a low titer was found for n-BuLi, attributable to this side... 

The site and extent of metallation of organolithium compounds can be determined by adding an alkyl iodide, typically Mel, to a solution of the organometallic compound and. 

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