Dilithium tetrachlorocuprate

The trans-selectivity of the Grignard coupling can be increased by addition of copper salts such as CuCN or dilithium tetrachlorocuprate. 

Chloromagnesium chloride Sodium hydride Dilithium tetrachlorocuprate(II) 2,6-Dichlorobenzenethiol... 

Organometallic Reagents. The major product of the Dilithium Tetrachlorocuprate(II)- or Copper(I) /odide-catalyzed Grignard reaction in THF or ether at low temperature arises from epoxide opening rather than from direct tosylate displacement (Table... 

This new coupling procedure was used in a recent stereoselective synthesis of a sex attractant of the codling moth, leans,trans-i, 10-dodecadiene-1 -ol(4).2 Thus coupling of (1) with (2) catalyzed by dilithium tetrachlorocuprate gave (3) in 85 % yield. This product consisted of 78 % of the desired trans,trans-isomer. Hydrolysis of the protective group (p-TsOH in aqueous methanol) gave the free alcohol (4) containing about 80% of the desired tains,(row-alcohol. The pure alcohol (4) was obtained by crystallization from pentane at - 5°. 

The first straight-chain A5,9 fatty acid to be synthesized was actually the (5Z,9Z)-5,9-hexacosadienoic acid [47]. The methodology developed by Djerassi et al. is shown in Fig. (17). This six-step synthesis started with the unusual controlled ozonolysis of one of the double bonds of (lZ,5Z)-l,5-cyclooctadiene to secure a 100% Z stereochemistry for what eventually was going to be the A9 double bond of the target molecule. Transformation of the product to the tosylated acetal, followed by Grignard coupling under dilithium tetrachlorocuprate catalysis afforded (Z)-4-heneicosenal, which after Wittig olefination with 4-carboxybutyltriphenylphosphonium bromide resulted in the desired A5,9... 

Coupling. Dilithium tetrachlorocuprate can be used to couple allylmagnesiutn bromide with a.tu-dibromoalkanes to provide o>-bromoalkenes. Vinylic tellurides have also been used as coupling partners. ... 

On the other hand, bromoalkanes react with saturated or ethylenic Grignard reagents in tetrahydrofuran in the presence of a suitable catalyst (dilithium tetrachlorocuprate 8-19) ... 

Diketones, 297 Dilithioacetate, 60, 175-176 Dilithium dicarbamates, 304 Dilithium tetrachlorocuprate, 176 Dilithium tetiachloiopalladate, 176-178... 

CARBOXYLIC ACIDS Dilithium tetrachlorocuprate. Tetra-n-butylammonlum iodide. CHLOROEPOXIDES /-Butyl hypochlorite. 

Dilithium tetrachlorocuprate s, under Mg Cuprous halide s. a. under Mg... 

The dilithium tetrachlorocuprate (Li2CuCl4)-catalyzed alkylation of a,ct)-dihalides with Grignard reagents allows simple halopolycarbon homologation of organic structures (Friedman and Shani, 1974). The reaction is... 

The ease with which the coupling reaction takes place is profoundly influenced by the kind of organic moieties and the nature of the transition metal catalysts (Tamura and Kochi, 1971c Kochi, 1974). Silver nitrate is an effective catalyst for the homocoupling reaction, whereas dilithium tetrachlorocuprate... 

Dilithium tetrachlorocuprate is recommended as an additive for cross coupling of Grignard compounds with tosylates even allylic and benzylic acetates give good yields . a-Methylene-ketones, -carboxylic acids and -lactones have been prepared via sulfides and sulfoxides. A convenient and general synthesis of acetylene derivatives from boranes via the reaction of iodine with lithium 1-alkynyltriorganoborates has been published ar-Nitrostyrenes can be easily obtained by a Wittig synthesis with formaldehyde in an aqueous medium . A new synthesis of unsym. ketones by reaction of dialkyldiloroboranes with lithium aldimines has recently been published . Metallo aldimines have also served for the synthesis of a variety of other compound classes such as a-hydroxyketones, a-keto acids, nitriles, and for the asym. synthesis of a-amino acids . Polycondensations of malononitriles with benzylic chlorides have been carried out quantitatively under mild conditions in dimethyl sulfoxide with triethylamine as acid acceptor . Carbonyl compounds can react with dibromoacetonitrile to yield a-bromo esters with additional carbon atom . ... 

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