Copper salts reagents

Use Agriculture (soil additive, pesticides, Bordeaux mixture), feed additive, germicides, textile mordant, leather industry, pigments, electric batteries, electroplated coatings, copper salts, reagent in analytical chemistry, medicine, wood preservative, preserva-... 

The Sandmeyer reaction is based on the replacement of the diazonium group in aryldiazonium salts by chloro, bromo, or cyano groups. Copper salt reagents are used ... 

Reactions of the Hydroxyl Group. The hydroxyl proton of hydroxybenzaldehydes is acidic and reacts with alkahes to form salts. The lithium, sodium, potassium, and copper salts of sahcylaldehyde exist as chelates. The cobalt salt is the most simple oxygen-carrying synthetic chelate compound (33). The stabiUty constants of numerous sahcylaldehyde—metal ion coordination compounds have been measured (34). Both sahcylaldehyde and 4-hydroxybenzaldehyde are readily converted to the corresponding anisaldehyde by reaction with a methyl hahde, methyl sulfate (35—37), or methyl carbonate (38). The reaction shown produces -anisaldehyde [123-11-5] in 93.3% yield. Other ethers can also be made by the use of the appropriate reagent. 

Metathesis of the trifluoromethylcadmium or tnfluoromethylzinc reagent with copper (I) salts gives solutions of trifluoromethylcopper [210] (equation 140). Depending on the stoichiometry and copper salt used, either CF3CU L or (Cp3)2Cu can be produced [211],... 

R Cu, or litliium or magnesium homocuprates RfCuM fM = Li, MgX), are fre-quently used, but a number of catalytic processes have also been developed. These processes nornnally utilize a catalytic amount of a copper salt CuY and a stoichiometric amount of an organometallic reagent R M IM = Li, MgX, ZnX, etc.). Hie leaving groups used include balides, esters, sulfonates, and epoxides, among others. 

Especially in the early steps of the synthesis of a complex molecule, there are plenty of examples in which epoxides are allowed to react with organometallic reagents. In particular, treatment of enantiomerically pure terminal epoxides with alkyl-, alkenyl-, or aryl-Grignard reagents in the presence of catalytic amounts of a copper salt, corresponding cuprates, or metal acetylides via alanate chemistry, provides a general route to optically active substituted alcohols useful as valuable building blocks in complex syntheses. 

The combination of copper salts and snlfnric acid is another widely used charring reagent. For preparation, 10 ml of concentrated H2SO4 has to be mixed carefully with 90 ml of acetic anhydride. Three grams of copper-II-acetate is dissolved in 100 ml of 8% phosphoric acid. After plate dipping or plate spraying, 15 min of heating at 125°C is recommended [17]. 

Generally, organocopper compounds can be prepared by transmetallation between copper salts and organometallic reagents such as RLi, RMgX, and RZnX.53,53a,53b Copper alkynides can be obtained by reaction of terminal alkynes... 

This reaction is very sensitive to water because in the presence of water and a metal salt (such as copper salt) the thioacetal tends to decompose, and this may reduce the amount of thioacetal available for epoxidation. When water is excluded from all the reagents, the reaction can be carried out in the presence of a catalytic amount of thioacetal. Otherwise, a stoichiometric amount of thioacetal compound is required. Scheme 4 53 summarizes the epoxidation of aldehydes using 138 as the chiral-inducing reagent. Excellent enantioselectivities are obtained in most cases. 

The related zinc cuprates formed from diorganozinc reagents and copper(I) cyanide also undergo smooth SN2 substitution reactions with propargyl oxiranes in the presence of phosphines or phosphites (Scheme 2.12). These transformations can also be performed with catalytic amounts of the copper salt since no direct reaction between the organozinc reagent and the substrate interferes [31, 34], and therefore should also be applicable to functionalized organozinc compounds. 

Alexakis and co-workers method using Grignard reagents in the presence of catalytic amounts of copper salts [8h-j] cannot be used for substrates of type 27 since direct nucleophilic attack at the oxirane ring prevails. 

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