Telomerization with olefins

In addition to the applications reported in detail above, a number of other transition metal-catalyzed reactions in ionic liquids have been carried out with some success in recent years, illustrating the broad versatility of the methodology. Butadiene telomerization [34], olefin metathesis [110], carbonylation [111], allylic alkylation [112] and substitution [113], and Trost-Tsuji-coupling [114] are other examples of high value for synthetic chemists. 

The trichloromethyl group can be reduced to either the dichloro- or the monochloromethyl group by proper choice of the SSE 49 s With ammonium nitrate the dichloro compounds are formed in 64—94% yield, while with tetra-metliylammonium chloride as supporting electrolyte the monochloro derivatives are obtained in 63 to 95% yield. As trichloromethyl compounds are readily available by telomerization of olefins with CC14) this reduction opens a simple route to a, co-bifunctional aliphatic compounds. 

Table VII. Telomerization of Ethylene with Olefinic Telogens ...

Z. Linyang, W. Fuss, K.L. Kompa, KrF laser induced telomerization of bromides with olefins. Ber. Bunsenges. Phys. Chem. 94, 867 (1990)... 

Carbon tetrachloride forms telomers with ethylene and certain other olefins (14—16). The mixture of Hquid products derived from ethylene telomerization may be represented CCl2(CH2CH2) Cl ia which nis 2l small number. Reaction of ethylene and carbon tetrachloride takes place under pressure and is induced by the presence of a peroxygen compound, eg, ben2oyl peroxide (17—19) or metal carbonyls (14,15). 

Homolytic cleavage of dlazonlum salts to produce aryl radicals is induced by titan1um(III) salt, which is also effective in reducing the a-carbonylalkyl radical adduct to olefins, telotnerization of methyl vinyl ketone, and dimerization of the adduct radicals. The reaction can be used with other electron-deficient olefins, but telomerization or dimerization are important side reactions. 

Although sulfonyl chlorides add readily to unactivated olefins, with vinylic monomers telomeric and/or polymeric products were observed. This difficulty has been overcome by carrying out the addition in the presence of catalytic amounts of CuCl2, so as to provide a general and convenient synthesis of /5-chlorosulfones (Asscher-Vofsi reaction)63. For the copper-catalyzed system a redox-transfer mechanism has been suggested in which the... 

YoshimuraN (2000) Telomerization (hydrodimeiization) of olefins. In Cornils B, Herrmann WA (eds) Applied homogeneous catalysis with organometallic compounds A comprehensive handbook. Special Workbench ed. Wiley-VCH, Weinheim. 

Linear oligomerization and telomerization of butadiene take place with nickel complexes in the presence of a proton source (7). In addition, cooligomerization of butadiene with functionalized olefins such as methacrylate is catalyzed by nickel complexes [Eq. (4)] (12, 13) ... 

The most characteristic reaction of butadiene catalyzed by palladium catalysts is the dimerization with incorporation of various nucleophiles [Eq. (11)]. The main product of this telomerization reaction is the 8-substituted 1,6-octadiene, 17. Also, 3-substituted 1,7-octadiene, 18, is formed as a minor product. So far, the following nucleophiles are known to react with butadiene to form corresponding telomers water, carboxylic acids, primary and secondary alcohols, phenols, ammonia, primary and secondary amines, enamines, active methylene compounds activated by two electron-attracting groups, and nitroalkanes. Some of these nucleophiles are known to react oxidatively with simple olefins in the presence of Pd2+ salts. Carbon monoxide and hydrosilanes also take part in the telomerization. The telomerization reactions are surveyed based on the classification by the nucleophiles. 

Although various transition-metal complexes have reportedly been active catalysts for the migration of inner double bonds to terminal ones in functionalized allylic systems (Eq. 3.2) [5], prochiral allylic compounds with a multisubstituted olefin (Rl, R2 H in eq 2) are not always susceptible to catalysis or they show only a low reactivity [Id]. Choosing allylamines 1 and 2 as the substrates for enantioselective isomerization has its merits (1) optically pure citronellal, which is an important starting material for optically active terpenoids such as (-)-menthol, cannot be obtained directly from natural sources [6], and (2) both ( )-allylamine 1 and (Z)-allylamine 2 can be prepared in reasonable yields from myrcene or isoprene, respectively, The ( )-allylamine 1 is obtained from the reaction of myrcene and diethylamine in the presence of lithium diethylamide under Ar in an almost quantitative yield (Eq. 3.3) [7], The (Z)-allylamine 2 can also be prepared with high selectivity (-90%) by Li-catalyzed telomerization of isoprene using diethylamine as a telomer (Eq. 3.4) [8], Thus, natural or petroleum resources can be selected. 

Jackstell R, Andreu MG, Frisch A, Selvakumar K, Zapf A, Klein H, Spannenberg A, Rottger D, Briel O, Karch R, Beller M (2002) A highly efficient catalyst for the telomerization of 1,3-dienes with alcohols first synthesis of a monocarbenepalladium(0)-olefin complex. Angew Chem Int Ed 41 986-989... 

The olefin can be regarded as a scavenger for the radicals produced during the photolysis process, and its reaction with the carbamoyl radical leads to the 1 1 adduct which is the higher amide. Telomers of different degrees of telomerization (mainly 2 1 to 4 1) were also formed in this reaction and supply additional proof for the free radical nature of the reaction, which is summarized in the following scheme ... 

In fact, alkylated succinamides were isolated in some cases, though in very poor yields, and result from radical combination, which is a chain termination step. The experimental observations, i.e. the formation of (a) 1 1 adducts, (b) telomeric products, (c) alkylated succinamides, and (d) oxamide (when an olefin is absent), are consistent with a free radical mechanism. The telomeric products obtained support the assumption that we deal here with a chain reaction, because they are characteristic products of this type of reaction. Another proof for the chain reaction mechanism is the fact that when benzophenone is used as a photoinitiator (vide infra), the amount of benzpinacol formed is smaller than the amount of the 1 1 addition product of formamide and olefin (16). Quantum yield determinations will supply extra evidence for the validity of a chain reaction mechanism for this photoaddition reaction. 

Several catalytic systems have been investigated for hydroamination of unsaturated bonds [16]. Takahashi et al. reported the telomerization of 1,3-dienes in the presence of an amine leading to octadienylamine or allylic amines when palladium catalysts are used in association with monodentate or bidentate phosphine ligands, respectively [17]. Dieck et al. demonstrated the beneficial effect of addition of an amine hydroiodic salt in the hydroamination reaction of 1,3-dienes in which the allylic amines are produced via an intermediate Jt-allyl palladium complex [18]. Coulson reported the Pd-catalyzed addition of amines to allenes where dimerization is incorporated [4]. This reaction presumably proceeds via a cyclic palladium intermediate in which the Pd activates the olefinic bond for nucleophilic attack the reactions are therefore different from pronucleophilic additions. 

The telomerization of fluorinated olefines with alcohols as telogens leads to co-hydroperfluoro alcohols ... 

Tsuji has completed three syntheses of zearalenone (119), all by quite similar routes. The first, shown in Scheme 1.28, began with acetate 59b, the minor product from the telomerization of butadiene in acetic acid. Cleavage to the alcohol and gas-phase dehydrogenation led to enone 141. Chain extension to 142 was accomplished in 70% yield by way of Michael addition of diethyl malonate to enone 141. Decarboalkoxylation and protection of the ketone then gave 143 (63%). Conversion of the ester to the primary tosylate 144 was achieved by conventional methods in 62% yield. A Wacker oxidation of the terminal olefin followed by reduction and exchange of the tosylate for an iodide then provided the aliphatic segment 145 in 64% yield. 

Oligomerizations, polymerizations and telomerizations are covered in other parts of this section, since C-C/C-C bond forming additions (dicarborations) are involved. Metal-mediated hydroalkylations of olefins with CH acidic compounds and hydroarylations with formal addition of aromatic C—H bonds to olefins are also known2, however, only a few examples of stereoselective applications have been reported (Section 1.5.8.2.6.). 

Telomerization of Conjugated Diolefins with Aromatics and Olefins Using Chelated Organosodium Catalysts... 

Telomerization of butadiene and isoprene with aromatics and olefins proceeds rapidly at 0°-100°C using organosodium catalysts in combination with aliphatic tertiary chelating polyamines containing two to six nitrogens. The products range from monoadduct up to tacky semisolids. 

This report covers the use of chelated organosodium compounds as novel catalysts for telomerizing conjugated diolefins with weak hydrocarbon acids such as aromatics and olefins (7). The factors affecting the chain-transfer reaction were of particular interest because one of our objectives was to increase selectivity to low-molecular-weight species. The products are useful in synthesizing plasticizer alcohols, flame retardants, and surface coatings. 

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