Copper® bromide catalyst

C for 20 hours. A catalyst system based on copper bromide, an amine, and oxygen was employed in these polymerizations, resulting in PPO yields as high as 83% and M s as high as 1.7 x 104 g/mol. 

A new heterocyclic system, 3 ,4-dihydro-3//-benzo[4,5]imidazo[l,2-f]oxazol-l-one 462, was synthesized by reaction of 4,4-dimethyl-5-methylene-l,3-dioxolan-2-one with o-phenylenediamine in the presence of copper bromide as catalyst in carbone dioxide at 60-80 °C under high pressure (Equation 217) <1999CHC216>. 

Copper bromide and pentakis-A-(heptadecafluoroundecyl)-l,4,7-triazeheptane (1 in Figure 10.9), along with an initiator, ethyl-2-bromoisobutyrate (2 in Figure 10.9), in a perfluoromethylcyclohexane-toluene biphase efficiently catalyse the polymerization of methyl methacrylate, with a conversion of 76 % in 5 h at 90 °C. The resultant polymer has a Mn = 11100 and a molar mass distribution of 1.30. After polymerization, the reaction was cooled to ambient temperature, the organic layer removed and found to contain a copper level of 0.088 % (as opposed to 1.5% if all the catalyst were to have remained in the polymer). A further toluene solution of monomer and 2 could be added,... 

The reaction with ammonia or amines, which undoubtedly proceeds by the SNAr mechanism, is catalyzed by copper8" and nickel105 salts, though these are normally used only with rather unreactive halides.106 This reaction, with phase transfer catalysis, has been used to synthesize triarylamines.107 Copper ion catalysts (especially cuprous oxide or iodide) also permit the Gabriel synthesis (0-58) to be applied to aromatic substrates. Aryl bromides or iodides are refluxed with potassium phthalimide and Cu 0 or Cul in dimethylacetamide to give N-aryl phthalimides, which can be hydrolyzed to primary aryl amines.108... 

Copper(i) bromide catalyst. Related examples have been described [12]. 

The coupling of ethylmagnesium bromide and ethyl bromide to n-butane follows overall third-order kinetics, being first order in each component and the copper(l) catalyst. There is no evidence for alkyl radicals in the copper(I)-catalyzed coupling process, and we propose the following two-step mechanism ... 

The reactivity of 6-haloimidazol[l,2-a]pyridine 135 towards different azoles can be modulated to give ipso product 136 in the presence of copper(l) catalyst or to yield cine product 137 in the absence of copper catalyst <03JOC5614>. Imidazo[l,2-a]pyrimidine 138 can be arylated at the 3-posltion with aryl bromides in the presence of cesium carbonate with catalytic palladium(II) acetate to give 139 <03OL4835>. 

When the 1,2-bis(trimethylsilyl)cyclopropene derivative 3 is used in the reaction with copper bromide as catalyst, the primary product, 1,5-bis(trimethylsilyl)tricyclo[2.1.0.02 5]pentan-3-one (4), can be desilylated with potassium fluoride in the presence of dibenzo-18-crown-6 to yield the parent ketone, tricyclo[2.1.0.02,5]pentan-3-one (5).10... 

Schmidt s group15 reported the first synthesis of the lactosyl ceramides 44 (Scheme 6). Reaction of excess n-tetradecylmagnesium bromide with 35 in THF at 60°C afforded a 1 1 mixture of d-arabino- and L-xylo-octadecanetetrol derivatives, 36a and 36b, respectively. Reactions at lower temperature or in different solvent did not result in a dramatic change in the ratio of 36a and 36b. It is interesting, however, that the addition of salts, such as the copper bromide-dimethyl sulfide complex or titanium tetrachloride, as a catalyst led... 

Copper bromide (CuBr) Copper monobromide Copper(l-i-) bromide Copper(l) bromide Cuprous bromide EINECS 232-131-6 HSDB 270. Used as a catalyst in organic reactions. Solid mp = 504° bp B 1345° d = 4.72 slightly soluble in H2O. Atomergic Chemetals Cerac Hoechst Celanese Sigma-Aldrich Fine Chem. 

Aryl halides containing less reactive halogen can also be converted into sulfides by thiols if heavy-metal (lead, zinc, mercury) thiols are used at 225-230° 1-naphthyl, 2-naphthyl sulfide,301 1- and 2-naphthyl phenyl sulfide,302 and 1-and 2-naphthyl o-, m-, and p-tolyl sulfide303 have been obtained in this way. When the heavy-metal thiolates are too stable and do not react with aryl bromides even at 240°, the aryl sulfides can nevertheless often be prepared by a generally applicable reaction of aryl iodides with sodium thiolates under the influence of copper as catalyst.304... 

A majority of the literature on ATRP focuses on the synthesis of styrene and its derivatives with copper-based catalysts. One of the most extensively studied systems is the polymerization of styrene conducted with CuBr, nitrogen-based ligands, and alkyl bromides as initiator. Better molecular weight control is obtained at low temperatures, presumably due to a lower contribution of thermal self-initiation during the early stage of the polymerization. For example, the reaction temperature can be lowered to 80-90 °C when efficient catalysts, such as CuBr/PMDETA, are used [19-22, 30]. 

Ethylaluminum dichloride Ethylaluminum sesquichloride Tetrabutyl titanate Tetraisopropyl titanate Triethylborane Trimethylaluminum catalyst, olefin polymers Tungsten hexachloride catalyst, olefin/diene polymerizationscatalyst olefin polymerizations Tri-n-hexylaluminum catalyst, olefinic addition Methanesulfonic acid catalyst, one-component RTV s Dibutyltin diisooctylmaleate catalyst, organic compounds chlorination Manganese chloride (ous), tetrahydrate catalyst, organic reactions Beryllium oxide Chromium oxide (ic) Copper bromide (ous) Copper phosphate (ic) Ferric chloride... 

PFA-Cg brush thin films were prepared by SI-ATRP in the presence of Ethyl 2-bromoisobutylate (EB) as a free initiator using Copper bromide / 4,4 -Dinonyl-2,2 bipyridyl (Cgbpy) catalyst, as shown in Scheme 19.2 [15,17]. Molecular weight and MWD of the PFA-Cg were determined by SEC of unbound polymers produced in the same reaction batch to be = 217,000 and = 2.20, respectively. The... 

Another way to induce torquoselectivity involves the use of chiral catalysts. In 2003, Aggarwal and Belfield disclosed the first asymmetric Nazarov reaction catalyzed by a chiral LA complex (Scheme 3.16) [19]. It was found that a complex formed between copper bromide and tridentate ligand 71 was capable of controlling the conrotation of the cyclization of precursor 70 in good enantioselectivity and yield. With substrate attached, the resulting complex 73... 

The following examples illustrate the scope of the Stille coupling. For example, triphenylarsine and/or copper co-catalysts are beneficial for the performance of stannanes. Triflates can be coupled in the presence of bromides. 

---