Alkylation with organic halides

E. Reacticms Involving Organometallic Compounds 1. Reaction of lithium alkyls with organic halides... 

A treatment of 314 with LDA yielded a carbanion stabilized by boron and sulfur atom, which undergoes alkylation with organic halides and with methyl acrylate (Equation (93)).473... 

The reaction occurs well below the temperature at which most of the parent metal carbonyls exchange with free CO and so is a direct nucleophilic attack on coordinated CO, although it may alternatively proceed via a prior electron path. The resulting acyl anions can be isolated as their [R4N] " or [ (C6H5)3P 2N] salts but are reactive and are used directly in subsequent alkylations with organic halides, acetylenes, a-/i-unsaturated carbonyls and alkyloxonium salts to form organic condensation products or metal-carbene complexes. 

Alkylation with organic halides carrying a second functional group affords a good synthesis of some difficultly obtained difunctional compounds including diamines, " amino halides, hydroxy amines, amino ketones, amino acids, " amino cyanides, and... 

S.3.2.7.2. by Modified Metal Halide-Catalyzed Alkylations with Organic Halides at a Boron Site. 

In Grignard reactions, Mg(0) metal reacts with organic halides of. sp carbons (alkyl halides) more easily than halides of sp carbons (aryl and alkenyl halides). On the other hand. Pd(0) complexes react more easily with halides of carbons. In other words, alkenyl and aryl halides undergo facile oxidative additions to Pd(0) to form complexes 1 which have a Pd—C tr-bond as an initial step. Then mainly two transformations of these intermediate complexes are possible insertion and transmetallation. Unsaturated compounds such as alkenes. conjugated dienes, alkynes, and CO insert into the Pd—C bond. The final step of the reactions is reductive elimination or elimination of /J-hydro-gen. At the same time, the Pd(0) catalytic species is regenerated to start a new catalytic cycle. The transmetallation takes place with organometallic compounds of Li, Mg, Zn, B, Al, Sn, Si, Hg, etc., and the reaction terminates by reductive elimination. 

Organolithium reagents (Section 14 3) Lithi um metal reacts with organic halides to pro duce organolithium compounds The organic halide may be alkyl alkenyl or aryl Iodides react most and fluorides least readily bro mides are used most often Suitable solvents include hexane diethyl ether and tetrahy drofuran... 

Acidic chloroaluminate ionic liquids have already been described as both solvents and catalysts for reactions conventionally catalyzed by AICI3, such as catalytic Friedel-Crafts alkylation [35] or stoichiometric Friedel-Crafts acylation [36], in Section 5.1. In a very similar manner, Lewis-acidic transition metal complexes can form complex anions by reaction with organic halide salts. Seddon and co-workers, for example, patented a Friedel-Crafts acylation process based on an acidic chloro-ferrate ionic liquid catalyst [37]. 

Polarization also occurs in coupling and disproportionation reactions of Grignard reagents with alkyl halides. The vinyl protons of isobutene produced in the reaction of t-butylmagnesium chloride with t-butyl bromide show A/E polarization as do the methyl protons of isobutane (Ward et al., 1970). Similar results arise in the reaction of diethyl-magnesium with organic halides (Kasukhin et al., 1972). 

Ni-cyclam, Ni(CR), or Ni(tet a) can be used efficiently as catalyst in DMF, and in the presence of NH4CIO4 as proton source [71-74]. Ni species generated electrochemically react rapidly with organic halides to generate alkyl, alkenyl, or aryl radicals which add intramolecularly to a double or triple bond, then leading to cyclopentanoids (Table 7, entries 3-7a). 

Some neutral metal carbonyls, particularly coordinatively unsaturated ones, are sufficiendy nucleophilic to undergo reaction with organic halides. Sigma-alkyl species which undergo subsequent CO insertion are formed by such reactions27. Hence, carbonylations... 

Alkylation of Organic Halides with Potassium Tricyanomethanide. The preparation of 1,1,1 - tricy anobutene-3 is given as a typical example of the experimental procedures used in the reaction of organic halides with potassium tricyanomethanide. 

Lithium Alkyl Cuprates. These important species are commonly used in ether or a similar solvent for a wide variety of organic syntheses. They are especially useful for C—C bond formation by interaction with organic halides ... 

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