0-bromo-6- phenyllithium

Reaction of 1-bromo- and l-chloro-2-(4-morpholino)-l,2-diphenyl-ethene with phenyllithium in benzene to give 2-(4-morpholino)-l,2-diphenyl-ethene [202]. 

Ethereal phenyllithium, prepared from lithium and bromo-benzene,3 may be standardized by adding an aliquot to water and titrating with standard sulfuric acid. 

Metalation. Benzene reacts with alkali metal derivatives such as methyl or ethyUithium in hydrocarbon solvents to produce phenyllithium [591-51-5], C6H5Li, and methane or ethane. Chloro-, bromo-, or iodobenzene will react with magnesium metal in ethereal solvents to produce phenylmagnesium chloride [100-59-4], C6H5MgCl, bromide, or iodide (Grignard reagents) (32). 

The submitters report that 9-bromo-9-phenylfluorene of poorer quality can also be prepared on an identical scale in a lower yield using phenyllithium (obtained from Aldrich Chemical Company, Inc.) following the procedure given in Step A with... 

Several halo-aryllithium compounds are explosive in the solid state in absence or near-absence of solvents or diluents, and operations should be designed to avoid their separation from solution. Such compounds include m- and p-bromo-, m-chloro-, p-fluoro-, m- and p-trifluoromethyl-phenyllithiums [1] and 3,4-dichloro-2,5-dilithio-thiphene [2], but m-bromo- and o-trifluoromethyl-phenyllithium appear to be explosive in presence of solvent also [1,3]. The m- and p-dilithiobenzenes are also explosively unstable under certain conditions. Most organolithium compounds are... 

This reaction was easily extended to produce substituted cyclic ethers in a one-pot synthesis (Scheme 3). Thus, by carrying out the carbonylation of phenyllithium in the presence of l-bromo-3-chloropropane at — 78 °C, the lithium enolate intermediate 3 was obtained which cyclizes to 4 by warming up the reaction mixture. 

Halogen-metal interconversion sometimes occurs prior to the coupling reaction. " Thus, phenyllithium and benzyl bromide react to give bromo-benzene and bibenzyl rather than diphenylmethane. ... 

Diketones.1 1,5-Diketones are obtained in the same way by use of N,N,N, N -tetramethylgluiaramide instead of N,N,N, N -tetramethylsuccinimide. Again, highest yields of 1,5-diketones were obtained by use of 6-bromo-2-pyridyllithium as the organolithium compound. In this case phenyllithium gave a reasonable yield of a... 

A procedure better adapted to operation on a large scale is described by Bavin. A solution of 1 mole of fluorene in 500 ml. of ether is added with stirring under reflux to an ethereal solution of phenyllithium prepared from 1.5 moles of bromo-benzene. After 1 hr. more the orange solution of metallated hydrocarbon is poured as rapidly as possible into powdered dry ice which has been slurried with ether. The mixture is acidified, the solvent removed by steam distillation, and the solid is dissolved in aqueous potassium carbonate solutioa Clarification with Norit gives a pale yellow solution which is poured into excess 30% hydrochloric acid. The colorless, crystalline product on reaction with methanol and hydrogen chloride gave the pure methyl ester, m.p. 64-65°. The yield was generally over 70% and occasionally reached 90%. ... 

The formation of lithium enolates 158 by treatment a-chloro- or a-bromo esters with metallic lithium was studied by Villieras, Normant, and coworkers. The protocol is also applicable to a-dichloro esters [156]. Magnesium enolates 159 with cM-configuration obtained analogously from a-bromoketones and magnesium were characterized by NMR spectroscopic data by Fellmann and Dubois [157]. In certain cases and low temperatures, the bromine-lithium exchange in a-bromo carbonyl compounds has been accomplished by treatment with phenyllithium or -butyllithium, while a competing addition to the carbonyl group could be suppressed (Scheme 2.46) [158]. 

Halogen/metal permutation and hydrogen/metal permutation (usually apostrophed as "metalation") dominate the interconversion methods. They employ organoalkali reagents such as phenyllithium, methyllithium, -butyllithium, iec-butyllithium, or the superbasic LIC-KOR mixture. However, even if commercial, these reagents have to be made beforehand. The reaction of a chloro- or bromo-substituted hydrocarbon with lithium, sodium, or magnesium offers a standard entry to them. Thus, ultimately one always has to revert to the metal. 

The intermediacy of cyclohexyne or cyclopentyne in the decomposition of, respectively, 2-fluoro- or 2-chloro-l-cyclohexenyllithium and 2-bromo-l-cyclopentenyllithium is hypothetical. The adducts obtained upon treatment with phenyllithium and lithium benzenethiolate may result from an addition/elimination rather than from an elimination/addition sequence. The reaction order, a kinetic gold standard, is not the same in DEE and THF. Moreover, whatever the number, it is treacherous as long as the aggregation state of the organolithiums is unknown. 

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