Copper halide complex, synthesis

Examples of preparation of copolymers are scarce. Mun et al. [81, 82] showed that the binary system of cobaltocene/ bis(ethylacetoacetato) copper (II) effectively initiates the living radical polymerizaton of MMA at 25 °C in acetonitrile. The polymerization activity of this initiator system was markedly affected by the solvent used. The synthesis of PMMA-b-PS copolymers with molecular weights reaching 700000 was successfully attempted by adding styrene to the living PMMA. The yield of the copolymers reached 80% when the MMA polymerization was carried out for three days. The same team [91] also synthesized PS-b-PMMA copolymers from the polymerization of MMA with polystyrene obtained in the presence of reduced nickel/halide systems. The yields range from 84 to 91% depending on the halide complex used. 

Lithium alkynylcuprates react with haloallenes to give similar skipped diacetylenes (see below). The related skipped enynes can be prepared by treatment of (pentadienyl)iron(tricarbonyl) halide complexes with dilithium trialkynylcuprates, the compounds being isolated as the iron(tricarbonyl)(diene) complexes (Scheme 4). Further examples of alkylation reactions of copper alkynides are illustrated in Scheme 5. Reaction between a lithium cyanoaikynecuprate and an iodoallene leads to a skipped diacetylene. This useful reaction has been used by Corey in his synthesis of hybridalactone (Scheme 6). °... 

The above DMC synthesis using MN was discovered at UBE, and a plant based on this technology has recently gone onstream with a capacity of about 6000ton/yr. Reaction (7) is catalyzed by supported palladium(II) halide complexes, which allow high (90-95%) CO selectivity. The addition of a cocatalyst such as copper chloride is required to prevent the reduction of Pd(II) to Pd(0) because Pd(0) tends to accelerate the formation of DM0. 

Synthesis of l,4-diacetoxy-2-butene by stoichiometric reaction of a halide complex was considered in an early period [8], and then some catalysts were developed. Although there are a series of Phillips patents, which include the InBrg-LiBr catalyst system, the l,4-diacetoxy-2-butene production rate was low and the 1,4-selectivity did not exceed 80%. The reaction of this system was summarized by Stapp [9] for example, the reaction using Cu(OAc)2-LiX-based catalysts proceeds by a copper-based redox cycle (Scheme 10.1). In addition, 20s-CuBr2-KBr, CuBr2-NaBr, and Ag(OAc)2-LiOAc were known for diacetoxylation, but either 1,4-selectivity or reaction rate was low. Furthermore, l,4-dichloro-2-butene is obtained in the production of chloroprene from 1,3-butadiene. 

Reaction of Arylamines Copper-catalyzed C—N coupling affords powerful tool for the synthesis of nitrogenated compounds [33]. In 1987, Paine reported soluble cuprous ion as the active catalytic species in Ullmann coupling [34]. Soluble air-stable copper(I) complex, Cu(PPh3)jBr, has been used for the synthesis of functionalized diaryl and triaryl amines (Scheme 20.17) [35]. Copper(I) complexes 7-8 and CuI-PBu have been employed for the coupling of aryl halides with aiyl amines [36, 37]. The catalyst with PBu could be used for the coupling of less reactive aiyl chlorides in the presence of KOTlu. 

Available information on the mechanism of cyclocondensation is rather contradictory. According to one hypothesis, both the condensation of aryl halides with copper acetylides and the cyclization occur in the same copper complex (63JOC2163 63JOC3313). An alternative two-stage reaction route has also been considered condensation followed by cyclization (66JOC4071 69JA6464). However, there is no clear evidence for this assumption in the literature and information on the reaction of acetylenyl-substituted acids in conditions of acetylide synthesis is absent. 

The original Sonogashira reaction uses copper(l) iodide as a co-catalyst, which converts the alkyne in situ into a copper acetylide. In a subsequent transmeta-lation reaction, the copper is replaced by the palladium complex. The reaction mechanism, with respect to the catalytic cycle, largely corresponds to the Heck reaction.Besides the usual aryl and vinyl halides, i.e. bromides and iodides, trifluoromethanesulfonates (triflates) may be employed. The Sonogashira reaction is well-suited for the synthesis of unsymmetrical bis-2xy ethynes, e.g. 23, which can be prepared as outlined in the following scheme, in a one-pot reaction by applying the so-called sila-Sonogashira reaction ... 

The Ullman reaction has long been known as a method for the synthesis of aromatic ethers by the reaction of a phenol with an aromatic halide in the presence of a copper compound as a catalyst. It is a variation on the nucleophilic substitution reaction since a phenolic salt reacts with the halide. Nonactivated aromatic halides can be used in the synthesis of poly(arylene edier)s, dius providing a way of obtaining structures not available by the conventional nucleophilic route. The ease of halogen displacement was found to be the reverse of that observed for activated nucleophilic substitution reaction, that is, I > Br > Cl F. The polymerizations are conducted in benzophenone with a cuprous chloride-pyridine complex as a catalyst. Bromine compounds are the favored reactants.53,124 127 Poly(arylene ether)s have been prepared by Ullman coupling of bisphenols and... 

TMC ATRA reactions can also be conducted intramolecularly when alkyl halide and alkene functionalities are part of the same molecule. Intramolecular TMC ATRA or atom transfer radical cyclization (ATRC) is a very attractive synthetic tool because it enables the synthesis of functionalized ring systems that can be used as starting materials for the preparation of complex organic molecules [10,11], Furthermore, halide functionality in the resulting product can be very beneficial because it can be easily reduced, eliminated, displaced, converted to a Grignard reagent, or if desired serve as a further radical precursor. The use of copper-mediated ATRC in organic synthesis has been reviewed recently and some illustrative examples are shown in Scheme 3 [10,11,31,32,33],... 

ARGET ATRP has been successfully applied for polymerization of methyl methacrylate, ft-butyl acrylate and styrene in the presence of Sn(EH)2 (10 mol% vs. alkyl halide initiator or 0.07 mol% vs. monomer) [164,165]. For all monomers, polymerizations were well controlled using between 10 and 50 ppm of copper complexes with highly active TPMA and Me6TREN ligands. ARGET ATRP has also been utilized in the synthesis of block copolymers (poly(n-butyl acrylate)— -polystyrene and polystyrene-Z -poly(n-butyl acrylate) [164,165] and grafting... 

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