Organolithium compounds synthesis

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

Organomagnesium and organolithium compounds are strongly basic and nucleophilic. Despite their potential to react as nucleophiles in SN2 substitution reactions, this reaction is of limited utility in synthesis. One limitation on alkylation reactions is competition from electron transfer processes, which can lead to radical reactions. Methyl and other primary iodides usually give the best results in alkylation reactions. 

Summary Fluorosilylamines and -hydrazines react with organolithium compounds to yield stable lithium derivatives. Perfluoro (Si-N) four- and six-membered ring systems are obtained with SiF4. The synthesis and crystal structures of the compounds are discussed. 

An efficient primary amine synthesis via iV-diisobutylaluminium imines has been described. A cyanide R CN (R1 = Bu, CsHn, Ph, 2-furyl or 2-thienyl) is treated with diisobutylaluminium hydride and the product is converted into the amine by reaction with an organomagnesium or organolithium compound R2M (R2 = Bu, t-Bu, allyl or benzyl)... 

SN2 reactions of primary organolithium compounds on PMMA in dilute homogeneous solution may be considered as a model system where all the important reaction parameters may be controlled they allow both a quantitative analysis of PMMA chain reactivity and the synthesis of well defined ketonic copolymers within a wide range of possible structural variations. The two homologous series of organolithium compounds and the corresponding reaction conditions we selected are given below ... 

Dehydrohalogenation reactions appeared to be a convenient route to double bond germanium nitrogen species and were commonly carried out with an organolithium compound as a base.3,4 5b 6 7 96,97 123 Accordingly, the synthesis of two moderately hindered stable germanimines Mes2Ge = NR 136 and 137 has been reported.59 Stabilization in these cases is achieved... 

The alkyllithium-initiated, anionic polymerization of vinyl and diene monomers can often be performed without the incursion of spontaneous termination or chain transfer reactions (1). The non-terminating nature of these reactions has provided methods for the synthesis of polymers with predictable molecular weights and narrow molecular weight distributions (2). In addition, these polymerizations generate polymer chains with stable, carbanionic chain ends which, in principle, can be converted into a diverse array of functional end groups using the rich and varied chemistry of organolithium compounds (3). 

We have previously reported the results of careful investigations of the solution carbonation (8) and oxidation (9) of polymeric organolithium compounds. These studies have been extended to the investigation of solid-state carbonation reactions and these results are reported herein. In addition, a new method has been developed for the synthesis of telechelic polymers with primary amine end-group... 

Grignard reaction and similar transformations allow C-C bond formation without a palladium catalyst. Grignard reagents and organolithium compounds are very versatile carbanion sources used in the synthesis of acyclic, heterocychc and carbo-cychc compounds. The esters, ketones and aldehydes are more stable when the reaction takes place on solid supports than in the hquid-phase, because this immo-bihzed components are not so sensitive towards water or oxygen. In the total synthesis of (S)-zearalenone (155) on solid supports the Grignard reaction is one of the key steps (Scheme 3.16) [120]. 

F. Totter and P. Rittmeyer, Organolithium Compounds—Industrial Applications and Handling , in Organometallics in Synthesis, A Manual (Ed. M. Schlosser), Wiley, New York, 2002. 

The presence of a specific organolithium compound in a synthetic process is sometimes assumed without isolation or further evidence other than having attained the expected product by a rationalized mechanism. For example, the synthesis of the alcohol depicted... 

The synthesis of thiophenol 326 according to equation 78 is assumed to proceed via an intermediate organolithium compound 325. There is a warning against trying to purify intermediate 325 and similar metallated compounds due to a danger of explosion . ... 

A particular case for the generation of a y-substimted organolithium compound, derived from an imine, was used for the synthesis of 2-substituted pyrrolidines. DTBB-catalyzed (5%) lithiation of y-chloro imines 196 yielded, after hydrolysis, 2-substituted pyrrolidines 198, including nomicotine (R = H, R = 3-pyridyl). The corresponding y-nitrogenated organolithium intermediate 197 was probably involved (Scheme 68). ... 

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