Copper alkoxides synthesis

Bacteriochlorins, 851 Barbituric acid metal complexes, 798 Barium alkoxides synthesis, 336 Barium complexes phthalocyanines, 863 porphyrins, 820 Becium homblei copper accumulation, 964 Benzaldehyde, 2-amino-self-condensation aza macrocycles from, 900 Benzamide, o-mercapto-metal complexes, 655 Benzamide oximes metal complexes, 274 Benzamidine, /V, V -diphenyl-metal complexes. 275 Benzene, 1,2-diamino-reactions with dicarbonyl compounds aza macrocycles from, 902 Benzene, 4 methylthionitroso-metal complexes, 804 Benzenedithiolates metal complexes, 605... 

Furthermore, the preparation and reactions of 2-methoxythiophene were studied by Sice (70). This compound was obtained by a copper catalysed Williamson synthesis. It was also found that iodothiophene reacted readily with sodium alkoxides, whereas bromothiophene reacted slowly and chlorothiophene did not react at all. Sodium iodide accelerated the reaction of bromothiophene. The ortho, para orienting alkoxy group on carbon atom 2 increased the directive influence of the sulphur atom to the 5 position but competed with it to induce some attack on the 3 position by electrophilic reagents (nitration, acylation). The acylation of 2-methoxythiophene with stannic chloride at low temperatures furnished a mixture of two isomers. The 5-methoxy-2-acetothienone was obtained in higher yield and was identified by its ultraviolet absorption spectrum. 

Tab. 10.8 summarizes the application of rhodium-catalyzed allylic etherification to a variety of racemic secondary allylic carbonates, using the copper(I) alkoxide derived from 2,4-dimethyl-3-pentanol vide intro). Although the allyhc etherification is tolerant of linear alkyl substituents (entries 1-4), branched derivatives proved more challenging in terms of selectivity and turnover, the y-position being the first point at which branching does not appear to interfere with the substitution (entry 5). The allylic etherification also proved feasible for hydroxymethyl, alkene, and aryl substituents, albeit with lower selectivity (entries 6-9). This transformation is remarkably tolerant, given that the classical alkylation of a hindered metal alkoxide with a secondary alkyl halide would undoubtedly lead to elimination. Hence, regioselective rhodium-catalyzed allylic etherification with a secondary copper(l) alkoxide provides an important method for the synthesis of allylic ethers. 

Previously published methods for the synthesis of dimethylzinc, a useful alkylating agent, include the reaction of dimethylmercury with metallic zinc,1 the reaction of a zinc-copper couple with methyl iodide,2 and the Grignard method.3 The reaction of trimethylaluminum with zinc(II) halides or alkoxides can be used,4 but it is more convenient to use zinc(ll) acetate, which is very readily obtained by dehydrating the commercial dihydrate with boiling acetic anhydride or by the reaction5 ... 

The direct electrochemical synthesis of metal alkoxides by the anodic dissolution of metals into alcohols containing conducting electrolytes was initially demonstrated by Szilard in 1906 for the methoxides of copper and lead.19 More recently the method has received some attention particularly in the patent literature.29-25 The preparation of the ethoxides of silicon, titanium, germanium, zirconium and tantalum by electrolysis of ethanolic solutions of NH Cl has been patented, although the production of the ethoxides was found to cease after several hours.24,25... 

Alcohol 6 is prepared by a copper-catalyzed reaction of (R)-benzylglycidyl ether with vinylmagnesium bromide. The first step here is a Williamson ether synthesis. The free alcohol 6 reacts with sodium hydride to a sodium alkoxide, which is treated with the sodium salt of bromoacetic acid. The acid is also converted into the sodium salt to avoid the formation of an ester as side product. After the reaction carboxylic acid 20 is released in 93 % yield by acidification with aqueous 10 % HC1 solution. 

Interestingly, the synthesis of the heterotrimetallic alkoxides of beryllium, which began in 1985 (8), was extended in 1988 to include heterotri- and tetra-metallic alkoxides of copper (25) as well as other 3d metals (26). These last two pioneering publications were included as invited papers in two reputed international journals, leading to almost universal acceptance of the formation of the stable species called heterometallic alkoxides (3, 4, 27-33). These al-... 

In view of the oxides of metals such as the alkaline earth, the lanthanides (e.g., Y and La), and copper being constituents of superconductors (366), a more intensive research was initiated for the synthesis of soluble and comparatively (with respect to monodentate) less hydrolyzable alkoxides of such metals as well. 

A-alkynylsulfonamides 174 are useful intermediates for diastereoselective synthesis <04OL727>. An efficient copper-promoted alkynylation of sulfonamide 173 has been developed to afford 174 with completely retained enantiomeric purity. The acetylene-titanium complexes 175, obtained from 174 upon treatment with titanium(II) alkoxide, react with aldehydes 176 to give alcohol 178, after hydrolysis, with virtually complete regio- and /Z-diastereoselectivity and also with high 1,5-diastereoselectivity (up to de = 98 2). The N-... 

Oligomerization becomes more and more important as the N-Z difference increases, that is, as the oxidation state Mz+ decreases. Divalent metals give insoluble polymeric alkoxides [Af(OR)2]n (Af2+ = Fe, Co, Ni, Cu,. ..). This was a real drawback for the sol-gel synthesis of high-Tc superconducting ceramics, such as YBa2Cu307-e. Bulky ligands, such as 2-(2-ethoxy-ethoxy)ethoxide had then to be used to prevent oligomerization and obtain soluble copper oxide molecular precursors [11]. 

Neils, T. L. L., and Burlitch, J. M., A soluble alkoxyzinc hydride, [HZnOCMesJa. Synthesis and reactions with copper(I) alkoxides, Inorg. Chem., 28, 1607 (1989). 

Sirio, C Poncelet, O., Hubert-Pfaizgraf, L. G., Daran, J. C., and Vaissermann, J., Reactions between copper p-diketonates and metal alkoxides as a route to soluble and volatile copper(II) oxide precursors Synthesis and molecular structure of Cu4( J-3,n -0C2H40iPr)4(acac)4 and (acac)Cu(p-OSiMe3)2Al(OSiMe3)2, Polyhedron, 11, 177 (1992). 

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