Substitution reactions organolithium compounds with

In theory a chain elongation of organolithium compounds with an arbitrary number of carbon atoms should be possible by substitution reactions with reagents of the type 23a and 23b. Such reagents are obtainable according to Scheme 30 With... 

The orientation in the reaction of organolithium compounds with 3-substituted pyridines had not always been unambiguously established. For example, it was reported that 3-picoline and phenyllithium combined to give 5-methyl-2-phenylpyridine (107, R = CH3) exclusively.240 This has been shown to be quite the opposite of what actually happens241 (see Table IV). Similarly, 3-phenylpyridine was said to... 

As described in Section II.A, the tandem sequence reaction of organolithium compounds with carbon monoxide followed by reaction with suitable electrophiles provides an useful tool for the preparation of diphenyldialkyl carbinols, and the reaction could be easily extended to produce substituted cyclic ethers in a one-pot synthesis. Thus, by carrying out the carbonylation of phenyllithium in the presence of conveniently substituted chloroalkyl bromides, Br(CH2)3+ Cl, at -78 °C, the oxo-lithiated intermediates 243 are obtained and cyclized to 244 by warming up the reaction mixture (Scheme 74)21. 

When CH3Li or n-BuLi is used in halogen-metal exchange, a rather electrophilic MeX or n-BuX is obtained as a by-product. The alkyl halide can undergo S 2 substitution with the organolithium compound as nucleophile to give the nucleophilic aromatic substitution product. However, Sn2 reactions of organolithium compounds with alkyl... 

Based on the results reported herein, it is concluded that the reaction of polymeric organolithium compounds with substituted alkyl chlorides in hydrocarbon solution at room temperature and above in the presence of lithium chloride is a useful, general functionalization methodology. 

The reaction of polymeric organolithium compounds with substituted DPE derivatives is an excellent system for development of a general functionalization reaction (eqn [39]) because... 

In conclusion, the addition reactions of simple and polymeric organolithium compounds with substituted 1,1-diarylethylenes provide a general method for the synthesis of a and co end-functionalized and labeled polymers. With this method in conjunction with appropriate protecting groups and reaction conditions, a wide variety of well-characterized, quantitatively functionalized and labeled polymers and copolymers can now be prepared with diverse molecular structures. Polymers can be prepared with functional groups either at the initiating chain end or at the terminating chain end. ... 

The reaction of polymeric organolithium compounds with substituted 1,1-di-phenylethylene derivatives (16) has been shown to be an excellent methodology for anionic synthesis of chain-end functionalized polymers (18) (Eq. 35)... 

The reaction of tnfluoromethyl-substituted A -acyl umnes toward nucleophiles in many aspects parallels that of the parent polyfluoro ketones Heteronucleophiles and carbon nucleophiles, such as enarmnes [37, 38], enol ethers [38, 39, 40], hydrogen cyanide [34], tnmethylsilylcarbomlnle [2,47], alkynes [42], electron-nch heterocycles [43], 1,3-dicarbonyl compounds [44], organolithium compounds [45, 46, 47, 48], and Gngnard compounds [49,50], readily undergo hydroxyalkylation with hexafluoroace-tone and amidoalkylation with acyl imines denved from hexafluoroacetone... 

Self-condensations are another set of important reactions of organolithium compounds. Tamao and Kawachi had reported that [(tert-butoxy diphenyl)silyl]lithium (20) exhibited ambiphUic character, and underwent a self-condensation reaction to give a [2- tert-butoxy)disilynyl]lithium derivative in THF as shown in Scheme 4, and also a nucleophilic substitution reaction with n-butyllithium . 

Acyclic and cyclic sp -hybridized ketal-containing y-functionalized organolithium compounds can be generated using an arene-catalyzed Uthiation at low temperature. In the case of acyclic precursors 171 (R = H) it was necessary to lower the temperature to -90 °C in the Uthiation step under DTBB catalysis (4%) in order to avoid decomposition of intermediates 172. Final electrophilic substitution reaction of these intermediates with electrophiles occurred with retention of configuration at temperatures ranging between... 

For aU the chiral intermediates above mentioned (253, 257 and 258) the reaction with prochiral electrophiles (aldehydes or differently substituted ketones) gave a c 1 1 mixture of diastereomers so, as occurred in other chiral functionalized organolithium compounds, the asymmetric induction is practically non-existent. 

Apart from nucleophilic substitution reactions, the chemistry of the halo derivatives of the 7r-deficient heterocycles is fairly similar to that of aromatic halides. Thus, heterobiaryls can be prepared by the Ullman reaction, and Grignard reagents and organolithium compounds can be prepared, although in many instances, and especially with Grignard reagents,... 

Another very important ring substitution reaction of ferrocene is its ability to undergo metalation with organolithium and organosodium compounds. Metalation with n-butyllithium in ethyl ether, first reported by Nesmeyanov and coworkers (63) and independently by Benkeser, Goggin, and Schroll (3),"leads to rather low yields of ferrocenyllithium (XXXI, M = Li) and l,l -ferrocenylenedi-lithium (XXXII, M = Li). It was subsequently shown by Mayo, Shaw, and... 

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