Halogen compounds olefinic

Halogen-substituted olefins may be obtained from hydrazones by the action ofN-halocompounds. 327, /. 328.372 (Chloro compounds of this type may also be made by the direct action of phosphorous pentachloride on the ketone, e.g. ref. 329, 330.)... 

A -Halogenated compounds such as iV-chlorotnfluoroacetamide, A -chloro-imidosulfuryl fluonde and N N dichlorotnfluoromethylamine add across C=C bonds to form saturated amides [14] tmidosulfury I fluorides [15] and amines [16], respectively Allylic halogenation also occurs with the use of A-bromo- or A-chIo roperfluoroamides The primary amine A,A-dichlorotrifluororaethylamine selectively affords 11 or 2 1 adducts with either tetrafluoroethylene or chlorotrifluoroethylene [16] (equation 7) The reaction mechanism is believed to involve thermal free radicals, with control achieved principally by reaction temperature The 1 1 adduct is formed even in the presence of a large excess of olefin... 

R.C. Paule, Kinetics of Peroxide-Catalyzed Addition Reactions of Halogenated Compounds to Olefins , Florida Univ Contract No nr-1017 (00), ONR (1956) 6) L.P. Kuhn C. Well-... 

Peroxidases have been used very frequently during the last ten years as biocatalysts in asymmetric synthesis. The transformation of a broad spectrum of substrates by these enzymes leads to valuable compounds for the asymmetric synthesis of natural products and biologically active molecules. Peroxidases catalyze regioselective hydroxylation of phenols and halogenation of olefins. Furthermore, they catalyze the epoxidation of olefins and the sulfoxidation of alkyl aryl sulfides in high enantioselectivities, as well as the asymmetric reduction of racemic hydroperoxides. The less selective oxidative coupHng of various phenols and aromatic amines by peroxidases provides a convenient access to dimeric, oligomeric and polymeric products for industrial applications. 

Metal-Halogen Counpounds. One of the few examples of an olefin insertion into a metal-halogen compound has been reported by Tsuji. The reaction, which also supports the idea that sigma-bonded metal-carbon compounds are intermediates in the palladium chloride-olefin oxidation reaction, was the addition of carbon monoxide to the ethylene palladium chloride 7r-complex in nonaqueous solvents to produce a moderate yield of 3-chloropropionyl chloride (96). 

Metal-Halogen Compounds. An unusual example of the addition of a metal halide to a conjugated diene has been reported. The complex formed from palladium chloride and butadiene has been shown to be a dimer of 1-chloromethyl-7r-allylpalladium chloride, (85). Whether this is a true insertion reaction or some type of ionic reaction has not been determined, but its close analogy with the olefin-palladium chloride insertion reaction mentioned above would suggest an insertion mechanism for the diene reaction also. 

The -elimination of hydrogen halides HX from organic halogen compounds yields olefins or acetylenes, depending on the structure of the starting substance and the number of HX molecules which have split off, viz. 

The formation of some of the halogen compounds of the olefines, and of hydrocarbons of the acetylene and benzene series, has already been alluded to on p. 48. 

Carbonyl compounds can undergo cross-coupling reactions with olefins [cf. 3.2.1.1] and halogen compounds, for example, with vinyl chloride 476> and CF3Br 477). 

The trimethylsilylated ylides (1), easily generated from trimethyl chlorosilane and ylides, react with aldehydes 2 to form vi-nylsilanes 3 (2,3). The vinylphosphonium silanolates 4 are also formed. Compounds 3 are versatile reagents for further reactions (4). The ylide J (with R1 =H) reacts with aldehydes 2 to give the dienes j). The oxidation of with the adduct 6, from triphenyl-phosphite and ozone, gives access to a generaT synthesis of acyl-silanes (trimethylsilylketones) (2). The silylated ylides react to form phosphonium salts 7 with halogen compounds. The salts 7.can be desilylated by fluorine ions. The disubstituted ylides JO Tormed can be converted in statu nascendi with aldehydes V[ into the tris-substituted olefin J2 (2,3). In the case of R3-I, vinyl... 

Both the automatic coulometric titration of petroleum streams and the continuous monitoring of pesticides and sulfur-halogen compounds indicate that the coulometric titrator method is amenable to the automatic maintenance of the concentration of a component in a solution system. A manual version of this approach has been used to study the kinetics of hydrogenation of olefins as well as to determine the rate of hydrolysis of esters.12 The latter system is a pH-stat that is based on the principles of coulometric titrations. Equations (4.9)-(4.11) indicate how this approach is applied to the evaluation of the rate constants for ester hydrolysis. A similar approach could be used to develop procedures for kinetic studies that involve most of the electrochemical intermediates summarized in Table 4.1. The coulometric titration method provides a convenient means to extend the range of systems that can be subjected to kinetic study in solution. 

With this type of shift reagent, the silver ion binds to soft Lewis base donors, such as olefins, aromatics, phosphenes, and halogenated compounds. At the same time, silver remains as an ion pair with Yb(fod)4 in a specific orientation such that a paramagnetic shift is induced in the resonances of the organic soft base. This method has proven to be useful for the separation of NMR resonance peaks of cis and trans geometric isomer mixtures of long-chain alkenes and complex mixtures of aromatic molecules [5]. 

Certain olefinic halogen compounds are best prepared by this method. Isobutylene bromide is dehydrohalogenated by hot potassium hydroxide... 

Peroxide-Induced Addition of Halogenated Compounds to Olefins. . 107... 

Certain halogenated compounds will condense with paraffinic, olefinic, or aromatic hydrocarbons. Catalysts for these reactions are of the Ftiedel-Crafts type. Thus, the condensation of alkyl halides with ethylene in the presence of aluminum chloride, zinc chloride, iron chloride, etc., furnishes higher alkyl halides. An example is the reaction of /-butyl chloride and ethylene to form l-chloro-3,3-dimethylbutane (75%). ... 

Reactive halogen compounds such as benzyl chloride, 2-thenyl chloride, 2-bromoacetylthiophene, (C HjS)COCH,Br , and 2-chloromethyl-thianaphthene (C,H5S)CHjCl are readily converted to esters by treatment with the sodium salts of carboxylic acids. A small amount of tri-ethylamine has proved to be an effective catalyst. Acetates are oftentimes made by heating halides with fused sodium acetate in glacial acetic acid, e.g., p-ethylbenzyl acetate (93%). The reaction is of little value for the preparation of simple aliphatic esters. Secondary and tertiary halides give increasing amounts of olefin by dehydro-halogenation. 

A. Olefinic compounds Acetylenic compounds Aromatic compounds Carbonyl compounds F/c-Oxygen compounds Nitrogen compounds Sulfur compounds Halogen compounds Other heteroatom compounds Organometallic compounds Stereoselective and Stereospecific Electrooxidation A. Carboxylic acids Acetoxylation Methoxylation Acetamidation... 

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