Dimethyl lithium cuprate

Lithium dimethyl cuprate, 209-215 Lithium diphenylarsenide, 341 Lithium diphenyl cuprate, 234 Lithium diphenylphosphide, 340-341, 645 Lithium diphenylphosphinate, 340 Lithium di-n-propyl cuprate, 245 Lithium ethynyltrialkylborates, 324-325 Lithium fluoride, 17... 

Alternative preparations of 2-allyl-3-methylcyclohexanone include a) lithium-ammonia reduction of 2-allyl-3 methylcyclohex-2-enone (see Note 13), which can be prepared by alkylation of 3-methjdcyclohex-2-enone or by alkjdation of 4-carboethoxy-3-methylcyclohex-2-enone [Hagemann s ester 2-Cyclohexene-l-carboxylic acid, 2-inethyl-4-oxo-, ethyl ester], followed bj hydrolysis and decarboxylation and b) conjugate addition of lithium dimethylcupratc [Cuprate (1-), dimethyl-, lithium] to 2-cyolohexen-l-one followed by trapping of the enolate with allyl iodide or allyl bromidein an appropriate solvent. 

Lithium(3,3-dimethyl-l-butynyl)-l,l-di-ethoxy-2-piopenyl cuprate, 300 Lithium dimethyl cuprate, 301-302 Lithium di-n-octylcuprate, 356 Lithium diphenylphosphide, 302 Lithium (fl-(E)-propenyl cuprate, 302-303 Lithium divinyl cuprate, 190 Lithium-Ethylamine, 284-286, 472 Lithium fluoride, 244 Lithium hexamethyidisilazide, 337 Lithium B-isopinocampheyl-9-borabi-cycloj 3.3.1) -nonyl hydride, 303 Lithium N-isopropylcyclohexylamide, 169 Lithium o-lithiobenzylate, 67 Lithium (l-lithiopropionate, 303 Lithium methyl mercaptide, 303-304 Lithium methylthioformaldinc, 305 Lithium naphthalenide, 303, 305-306 Lithium perchlorate, 212 Lithium n-propylmercaptide, 283 Lithium selenophenolate, 306-307 Lithium 2,2,6,6-tetramethylpiperidide, 299, 307-308... 

Related Reagents. 3,3-Diethoxy-1-propen 2 ylcopper Lithium Bis(3,3-diethoxy l-propen-2-yl)cuprate and Lithium (3,3-Diethoxy-1 -propen-2 yl) (3,3-dimethyl-1 -but5myl)cuprate for related heterocuprates, see Lithium Methyl(phenylthio) cuprate for discussion of lithium dialkylcuprates, see Lithium Dimethyl cuprate. 

DilithiumCyanobis(dimethylphenylsilyl)-cuprate Dimethylphenylsilyllithium Lithium Bis[dimethyl(phenyl)silyl]cuprate Lithium Cyano(dimethylphenylsilyl)cuprate E) 1-Trimethylsilyl-1,3-butadiene... 

Many other organometaUic compounds also react with carbonyl groups. Lithium alkyls and aryls add to the ester carbonyl group to give either an alcohol or an olefin. Lithium dimethyl cuprate has been used to prepare ketones from esters (41). Tebbe s reagent, Cp2TiCH2AlCl(CH2)2, where Cp = clyclopentadienyl, and other metal carbene complexes can convert the C=0 of esters to C=CR2 (42,43). 

Although ethereal solutions of methyl lithium may be prepared by the reaction of lithium wire with either methyl iodide or methyl bromide in ether solution, the molar equivalent of lithium iodide or lithium bromide formed in these reactions remains in solution and forms, in part, a complex with the methyllithium. Certain of the ethereal solutions of methyl 1ithium currently marketed by several suppliers including Alfa Products, Morton/Thiokol, Inc., Aldrich Chemical Company, and Lithium Corporation of America, Inc., have been prepared from methyl bromide and contain a full molar equivalent of lithium bromide. In several applications such as the use of methyllithium to prepare lithium dimethyl cuprate or the use of methyllithium in 1,2-dimethyoxyethane to prepare lithium enolates from enol acetates or triraethyl silyl enol ethers, the presence of this lithium salt interferes with the titration and use of methyllithium. There is also evidence which indicates that the stereochemistry observed during addition of methyllithium to carbonyl compounds may be influenced significantly by the presence of a lithium salt in the reaction solution. For these reasons it is often desirable to have ethereal solutions... 

One diastereomer 5 was formed in large excess (98-76% de) on addition of the 2-(l-dimethyl-aminoethyl)phenyl group from the corresponding lithium dialkylcuprate and or lithium alkyl(2-thienyl)cuprate to prostereogenic enones64. 

Lithium, methyl, 55,7, 10 Lithium, phenyl-, 55,11 Lithium phenylthio(alkyl)cuprates, 55,122 LITHIUM, phenyltluo(fe/f-butyl)cuprate [Lithium, phenylthio( 1,1 -dimethyl-ethyl)cupiate, 55,122 Lithium, 1-propenyl-, 55, 111 LITHIUM, ( >l-propenyl-, 55, 103 Lithium thiophenoxide [Ben7enethiol, lithium salt], 55, 122... 

Organobis(cupratesY, spiroannelation.16 1,4-Dilithiobutane, prepared from 1,4-dichlorobutane and lithium in ether at 0°, on reaction with copper thiophenoxide (2 equiv.) forms a biscuprate, formulated as 1 for convenience. This dimetallic reagent adds to 3-halo-5,5-dimethyl-2-cyclohexenones (2) to form the spiro-[4.5]decanone 3 in yields as high as 96%. Cuprates prepared from other Cu(I) sources are less efficient, as is the cuprate prepared from di-Grignard reagents... 

The results for conjugate additions to pseudodipeptides 83 and 86 may be interpreted along similar lines. Thus, addition of the fairly slim lithium dimethyl-cuprate nucleophile proceeded non-selectively (84, Scheme 6.17) [34, 35]. Con-... 

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