Styrenes copper chloride

To overcome the problems encountered in the homogeneous Wacker oxidation of higher alkenes several attempts have been undertaken to develop a gas-phase version of the process. The first heterogeneous catalysts were prepared by the deposition of palladium chloride and copper chloride on support materials, such as zeolite Y [2,3] or active carbon [4]. However, these catalysts all suffered from rapid deactivation. Other authors applied other redox components such as vanadium pentoxide [5,6] or p-benzoquinone [7]. The best results have been achieved with catalysts based on palladium salts deposited on a monolayer of vanadium oxide spread out over a high surface area support material, such as y-alumina [8]. Van der Heide showed that with catalysts consisting of H2PdCU deposited on a monolayer vanadium oxide supported on y-alumina, ethene as well as 1-butene and styrene... 

Photochemical decomposition of diazo(trimethylsilyl)methane (1) in the presence of alkenes has not been thoroughly investigated (see Houben-Weyl Vol. E19b, p 1415). The available experimental data [trimethylsilylcyclopropane (17% yield) and la,2a,3/J-2,3-dimethyl-l-trimethylsilylcyclopropane (23% yield)] indicate that cyclopropanation occurs only in low yield with ethene and ( )-but-2-ene.24 In both cases the formal carbene dimer is the main product. In reactions with other alkenes, such as 2,3-dimethylbut-2-ene, tetrafluoroethene or hexafluoro-propene, no cyclopropanes could be detected.24 The transition-metal-catalyzed decomposition of diazo(trimethylsilyl)methane (1) has been applied to the synthesis of many different silicon-substituted cyclopropanes (see Table 3 and Houben-Weyl Vol.E19b, p 1415).3-20a b-11 Copper chloride has been most commonly used for carbene transfer to ethyl-substituted alkenes, cycloalkenes, styrene, and related arylalkenes.3,203,15,21 25 For the cyclopropanation of acyl-substituted alkenes, palladium(II) chloride is the catalyst of choice, while palladium(II) acetate was less efficient, and copper chloride, copper(II) sulfate and rhodium(II) acetate dimer were totally unproductive.21 The cyclopropanation of ( )-but-2-ene represents a unique... 

The polymerization of styrene from benzyl chloride-POSS was run in 50% p-dimethoxybenzene at 120 using a copper chloride / N,N,N ,N N -penta-methyldiethylenetriamine (PMDETA) catalyst system. The kinetic and molecular weight plots are illustrated in Figures 5 and 6 respectively. They show that the concentration of active species was conserved throughout the polymerization in the absence of transfer reactions, and that the condition of fast initiation is not hampered by the inorganic fragment. 

Copper chloride, Diels-Alder catalyst, 144 Copper oxides, promoters for MA catalyst, 36 Cotton, poly(styrene-alt-MA) grafted, 476 Cotton fabric, MA condensation, 503 Coumaline see a-pyrone Coumaran see 2,3-benzofuran Coumarin, 100... 

Transition metal halides can also act as transfer agents. For example, copper(ii) chloride or iron(iii) chloride may be applied. Transfer coefficients for these two halides have been determined in DMF at 60 °C. For copper(ii) chloride, the transfer coefficients are C= 10", C= 10 and C= 10 for styrene, MMA and acrylonitrile, respectively. Iron(iii) chloride is less efficient and gives values of C=626, C=306, C=86, C=4 and C=2 for vinyl acetate, styrene, vinyl chloride, MMA and acrylonitrile, respectively. " The transfer process forms alkyl halides and metal species in lower oxidation states, the latter occasionally being capable of activating the former. Such a mechanism of reversible activation and deactivation is utilized in atom transfer radical polymerization (ATRP). 

Recently, Goddart et al. [6] reported a polyvinyl alcohol-copper(ll) initiating system, which can produce branched polymers on surfaces. The initiating system is prepared by dissolving polyvinyl alcohol in water that already contains copper nitrate (or copper chloride). The calcium carbonate filler is dipped into the solution and dried. If this is used for polymerization of an olefin (say, styrene), it would form a polymer that adheres to the particles, ultimately encapsulating them. The mechanical properties of calcium-carbonate-fiUed polystyrene have been found to depend strongly on filler-matrix compatibihty, which is considerably improved by this encapsulation. 

Chemical reduction is used extensively nowadays for the deposition of nickel or copper as the first stage in the electroplating of plastics. The most widely used plastic as a basis for electroplating is acrylonitrile-butadiene-styrene co-polymer (ABS). Immersion of the plastic in a chromic acid-sulphuric acid mixture causes the butadiene particles to be attacked and oxidised, whilst making the material hydrophilic at the same time. The activation process which follows is necessary to enable the subsequent electroless nickel or copper to be deposited, since this will only take place in the presence of certain catalytic metals (especially silver and palladium), which are adsorbed on to the surface of the plastic. The adsorbed metallic film is produced by a prior immersion in a stannous chloride solution, which reduces the palladium or silver ions to the metallic state. The solutions mostly employed are acid palladium chloride or ammoniacal silver nitrate. The etched plastic can also be immersed first in acidified palladium chloride and then in an alkylamine borane, which likewise form metallic palladium catalytic nuclei. Colloidal copper catalysts are of some interest, as they are cheaper and are also claimed to promote better coverage of electroless copper. 

This is one of the steps in the copper-catalyzed redox-transfer chain addition of arenesulfonyl chlorides to styrenes (vide infra). The p-value of + 0.56 indicates the involvement of a simple atom transfer as well as a polar contribution to the transition state. 

The copper-catalyzed additions of sulfonyl chlorides to conjugated dienes and trienes73 as well as to aryl-substituted cyclic olefins74 and substituted styrenes have been described75 for example, arenesulfonyl chlorides add to vinylarenes providing good to excellent yields75 of /J-chlorosulfones ... 

Reaction 31 appears to be little affected by substituent electronic effects or by steric effects of either sulfonyl chloride or styrenes. Treatment of /5-chlorosulfones with triethylamine in benzene affords the corresponding a, /5-unsaturated sulfones in excellent yield. The copper-catalyzed addition of sulfonyl iodides to simple and cyclic alkenes has also been exploited76. 

The square-planar complex (34) NiCI2-(P-/i-Bu3)2 was a better catalyst than the tetrahedral complex NiBr2 (PPh3)2 for hydrosilation of styrene with trichlorosilane at temperatures of 150°-170°C. A nickel(0) complex, Ni[P(OPh)3]4, was as good as NiCl2(NC5H5)4, which was best among known nickel catalysts for this reaction. Addition of copper(I) chloride... 

ETHYL 4-METHYL-E-4,8-NON-ADIENOATE, 53, 116 Styrene, reaction with carbe-thoxycarbene, 50, 94 Suberoyl chloride, 54, 88 SUBSTITUTION OF ARYL HALIDES WITH COPPER(I) ACETYLIDES ... 

This complex was generated by treatment of ligand 2, for example, with M-butyllithium followed by addition of 0.5 equiv of copper(II) chloride. This species was purified by column chromatography and used in 1 mol % (relative to ethyl diazoacetate) in the reaction between styrene (3 equiv) and ethyl diazoacetate (1 equiv). The results of these experiments are summarized in Table 9.1 (Fig. 9.11). As can be seen from these results, the yields range from 72-88%, the trans/cis ratios are all approximately equal ( 70 30), but the enantioselectivities for the isomers... 

The Meerwein arylation is at least formally related to the atom transfer method because a net introduction of an aromatic ring and a chlorine across a double bond is accomplished (Scheme 62). Facile elimination of HC1 provides an efficient route to the kinds of substituted styrenes that are frequently prepared by Heck arylations. Standard protocol calls for the generation of an arene diazonium chloride in situ, followed by addition of an alkene (often electron deficient because aryl radicals are nucleophilic) and a catalytic quantity of copper(II) chloride. It is usually suggested that the copper salt operates in a catalytic redox cycle, reducing the diazonium salt to the aryl radical as Cu1 and trapping the adduct radical as Cu11. 

Asymmetric cyclopropanation. Three laboratories have reported that copper complexes of chiral bis(oxazolines) are effective catalysts for asymmetric cyclopropanation of alkenes with diazoacetates. Bis(oxazolines) such as 1 are readily available by condensation of a-amino alcohols with diethyl malonate followed by cyclization, effected with dichlorodimethyltin or thionyl chloride. Cyclopropanation of styrene with ethyl diazoacetate catalyzed by copper complexes of type 1 indicates... 

A PEG-SCCO2 system has also been used in the aerobic oxidation of styrene (Figure 8.7). In the presence of cuprous chloride co-catalyst the reaction favours acetophenone formation, whereas in the absence of copper benzaldehyde is favoured. The catalyst could be recycled five times and it was suggested that the PEG acts to prevent the palladium catalyst from decomposing and also assists in product separation. 

A large number of styrenic monomers have been investigated in metal-catalyzed radical polymerizations. Polymerization of styrene (M-19) can be controlled with copper,28,84,85 152 176 ruthenium,57 60 62 66 86,205 iron,71 75 rhodium,86 140 rhenium,141 and molybdenum catalysts.144 The polymerizations have actively been studied with the copper-based systems, among which precisely controlled molecular weights and very narrow MWDs (MJMn =1.1) were obtained in a homogeneous system consisting of 1-13 (X = Br), CuBr, and L-3 in the bulk at 130 °C.85 Similar well-controlled polymerizations are feasible with several ruthenium (Ru-5)60 and iron (Fe-2,72 Fe-3,73 and Fe-471) complexes in conjunction with a bromide or iodide initiator. Even a chloride initiator (1-25, X = Cl) can afford narrow MWDs (MJMn =1.1) when coupled... 

The ABA-type block copolymers B-86 to B-88 were synthesized via termination of telechelic living poly-(THF) with sodium 2-bromoisopropionate followed by the copper-catalyzed radical polymerizations.387 A similar method has also been utilized for the synthesis of 4-arm star block polymers (arm B-82), where the transformation is done with /3-bromoacyl chloride and the hydroxyl terminal of poly(THF).388 The BAB-type block copolymers where polystyrene is the midsegment were prepared by copper-catalyzed radical polymerization of styrene from bifunctional initiators, followed by the transformation of the halogen terminal into a cationic species with silver perchlorate the resulting cation was for living cationic polymerization of THF.389 A similar transformation with Ph2I+PF6- was carried out for halogen-capped polystyrene and poly(/>methoxystyrene), and the resultant cationic species subsequently initiated cationic polymerization of cyclohexene oxide to produce... 

Poly(l,4-butadiene) segments prepared by the ruthenium-mediated ROMP of 1,5-cyclooctadiene can be incorporated into the ABA-type block copolymers with styrene (B-106) and MMA (B-107).397 The synthetic method is based on the copper-catalyzed radical polymerizations of styrene and MMA from the telechelic poly(butadiene) obtained by a bifunctional chain-transfer agent such as bis(allyl chloride) or bis-(2-bromopropionate) during the ROMP process. A more direct route to similar block copolymers is based on the use of a ruthenium carbene complex with a C—Br bond such as Ru-13 as described above.67 The complex induced simultaneous or tandem block copolymerizations of MMA and 1,5-cyclooctadiene to give B-108, which can be hydrogenated into B-109, in one pot, catalyzed by the ruthenium residue from Ru-13. 

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