Alkyl copper compounds

Allylic substitutions with nonstabilized C-nucleophiles are an important domain of organocopper chemistry [51]. However, on close inspection of the literature, it becomes apparent that regioselectivity in favor of the branched allylic alkylation products is only obtained with alkyl copper compounds, while aryl copper compounds mainly give the linear alkylation products. This observation was an incentive for Alexakis et al. [52] to probe the reactions of aryl zinc hahdes in the Ir-catalyzed allylic substitution (Scheme 9.18). 

Alkylcadmium alkoxides, 11 399-400 alkylperoxides, 11 399-400 anions, 11 370-371 halides, 11 377 solvated, 11 392-394 Alkylcalcium halides, solvated, 11 390 Alkyl complexes, osmium, 37 239-242 Alkyl copper compounds, 17 140, 142, 143 Alkyl derivatives, phosphoniuilic halides and, 1 363... 

Cut LiCl with lithium naphthalenide, it is possible to prepare allylic copper species that undergo smooth addition to enones leading to the 1,4-addition product such as 8 in 92% yield [11], Remote ester-functionalized aryl- and alkyl-copper compounds can be readily prepared by this method [12], Remarkably stable ortho-halophenylcopper reagents obtained by the direct insertion of activated copper undergo substitution reactions with alkyl iodides, benzylic bromides and various acid chlorides [13,14]. 

Fuel additives - [AMNES-CYCLOALIPHATIC AMINES] (Vol 2) - [SULFONIC ACIDS] (Vol 23) -arsenic compds as [ARSENIC COMPOUNDS] (Vol 3) -boron compds as [BORON COMPOUNDS - BORIC ACID ESTERS] (Vol 4) -coordination compounds as [COORDINATION COMPOUNDS] (Vol 7) -ethers m [ETHERS] (Vol 9) -magnesium alkyls as [MAGNESIUM COMPOUNDS] (Vol 15) -polyamines as [DIAMINES AND HIGHER AMINES ALIPHATIC] (Vol 8) -htanates as [TITANIUM COMPOUNDS - ORGANIC] (Vol 24) -use of copper compounds [COPPER COMPOUNDS] (Vol 7)... 

The most conspicuous property of aliphatic amines, apart from their fishy smell, is their high basicity, which usually precludes N-alkylations under acidic reaction conditions (last reaction, Scheme 6.3). Hence, alkylation of amines with tertiary alkyl groups is not usually possible without the use of highly stabilized carbocations which can be formed under basic reaction conditions. Rare exceptions are N-alkyla-tions of amines via radicals (Scheme 4.2), copper-catalyzed propargylations (Scheme 6.3), and the addition of amines to some Michael acceptors and allyl palladium or iridium complexes. Better strategies for the preparation of tert-alkylamines include the addition of Grignard reagents to ketone-derived imines [13] or the reduction of tert-alkyl nitro compounds. 

The aerobic oxidation of phenols in the presence of cobalt-Schiffs base complexes as catalysts is facilitated by (electron-donating) alkyl substituents in the ring and affords the corresponding p-quinones, e.g. the Vitamin E intermediate drawn in Fig. 4.87. When the para-position is occupied the reaction may be directed to the ortho-position [252, 253]. Copper compounds also mediate this type of oxidation, e.g. the Mitsubishi Gas process for the Vitamin E intermediate... 

Burdon et al. 31) have proposed that aryl and vinyl halides, but not alkyl halides, couple with copper compounds via a four-center transition state (XI). Nucleophilic substitution of vinylic bromides by organo-... 

Copper compound Alkyl halide 7o Yield coupled product References... 

The tosylate group can be displaced from alkyl tosylates by dialkyl-cuprates 256, 297, 301), presumably by attack at carbon by the d electrons of copper. A transient copper(III) intermediate may be formed [Eq. (87)], as suggested for similar reactions with alkyl halides. An analogous reaction was reported between a copper(I) carboxylate and an alkyl tosylate 185). (Carboxyethyl)methylcopper, C2H5O2CCH2CU, failed to react with butyl tosylate in THF 181). However, copper compounds of the type RCu are generally less reactive than the cuprates. 

Copper compounds containing carbon-bound ligands, such as cyanide, carbon monoxide, alkyls, and so on are covered elsewhere (see Copper Organometallic Chemistry). 

The decomposition of alkyl and aryl copper compounds has been the subject of much debate. Initially free radical mechanisms were advanced, such theories being supported by the reduced yields of hydrocarbons in the presence of benzoquinone or other free-radical scavengers (24, 150). However, under all conditions very poor yields of dimeric alkanes are obtained. These would be the likely products of a free-radical decomposition. 

The present reaction (B) can be carried out as follows For example, the starting 3-phenylpropylenes, the alcohols, the palladium catalysts and the optional amines or copper compounds are charged into a reaction vessel. The alkyl nitrites are added to the mixture, causing it to react under the predetermined reaction conditions. It should be noted, however, that the addition order of the above-mentioned reactants and catalysts is not specifically limited. 

The recovered unreacted starting materials and alcohols as well as the optional amines and copper compounds can be again used. Further, NO gas can be used in the production of the alkyl nitrites. 

The arylation of lower aliphatic alcohols was observed when the copper-catalysed decomposition of triarylbismuth diacetate was carried out in simple alcohols, used as solvent (20 mL per mmole of bismuth reagent). The yields of alkyl aryl ethers (based on the bismuth reagent) ranged from 60 to 95% for primary and secondary alcohols, but only 9% were obtained in the case of t rt-butyl alcohol.Under stoichiometric conditions, the 0-phenylation of 3-p-cholestanol by triphenylbismuth diacetate (1 equiv.) was not significantly improved upon addition of copper diacetate. 5 Different copper compounds, such as Cu(OAc)2, CuCl2, CuCl or metallic copper, can be used as effective catalysts. 

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