Zinc-Chlorotrimethylsilane

SULFOXIDES Chlorotrimethylsilane-Zinc. Cyanuric fluoride. Phosphorus triiodide. 

Reductive coupling of carbonyls to alkenes Titanium(IV) chloride-Zinc, 310 of carbonyls to pinacols Titanium(III) chloride, 302 Titanium(IV) chloride-Zinc, 310 of other substrates Samarium(II) iodide, 270 Reductive cyclization 2-(Phenylseleno)acrylonitrile, 244 Tributylgermane, 313 Tributyltin hydride, 316 Triphenyltin hydride, 335 Trityl perchlorate, 339 Reductive hydrolysis (see Hydrolysis) Reductive silylation Chlorotrimethylsilane-Zinc, 82... 

Chlorotrimethylsilane-Zinc, 82 Chromium(VI) oxide-Chlorotrimethyl-silane, 327... 

Metal-containing compounds, Zinc Compounds (Continued) (Carboethoxyalkyl)zinc iodide, 220 (Carboethoxyethyl)zinc iodide, 220 (Carboethoxypropyl)zinc iodide, 220 Chlorotrimethylsilane-Zinc, 82 (Cyanomethyl)zinc bromide, 221 Dibromomethane-Zinc-Copper(I) chloride, 93... 

SULFOXIDES Chlorotrimethylsilane- Zinc. Sodium borohydride-Cobalt(II) chloride. DESILYLATION Cesium fluoride. Potassium /-butoxide-Dimethyl sulfoxide. Potassium hydride. 

Preparative Methods from chlorotrimethylsilane, zinc, and XCH2CN, (X = Cl, 61% yield X = Br, 81% yield). ... 

A related reaction process involves the use of chlorotrimethylsilane in the presence of zinc dust in anhydrous THF31, in which the zinc functions as both an electron donor and a chlorine scavenger. The stoichiometry and a plausible mechanism for the reaction are given in equation (9) ... 

Selective silylation of polychloromethanes using reactive metal electrodes such as zinc and magnesium has also been reported as shown in Scheme 37 [76, 77]. The electroreduction of carbon tetrachloride and chloroform in the presence of chlorotrimethylsilane affords the monosilylated and disilylated products. The product selectivity seems to depend upon the electrode material. 

RCu(CN)ZnI.u These new copper reagents are prepared by reaction of primary or secondary iodides with zinc that has been activated with 1,2-dibromoethane and chlorotrimethylsilane. The resulting organozinc compounds are then allowed to react with the THF-soluble CuCN-2LiCl (equation I). Because of the mild conditions, these new reagents can be prepared from iodides containing keto, ester, and nitrile groups. 

Alkylzinc iodides These reagents are prepared by reaction of alkyl iodides with Zn/Cu in toluene-N,N-dimethylacetamide (DMA). In the presence of 1 equiv. of chlorotrimethylsilane they can add to aldehydes to form alcohols. DMA may be replaced as the cosolvent by N-methylpyrrolidone (NMP), but HMPT retards this reaction. This reaction can be used to obtain y-, 8-, and e-hydroxy esters from P-, y-, and 8-zinc esters (equation I). 

The a-arylamino nitriles 251, obtained from primary aromatic amines, trimethylsilyl cyanide and acetone in the presence of zinc chloride, react with methyllithium to give A-t-butylarylamines 252287. Af,Af-Bis(trimethylsilyl)amines 253 (R = allyl, benzyl, 3-phenylpropyl etc.) are formed in 50-88% yields by the action of chlorotrimethylsilane on primary amines in the presence of a catalytic amount of titanium(IV) chloride288. 

Clean the Erlenmeyer flask with deionized water and let it dry. Add 14.3 grams (or 0.25 moles) of activated zinc dust and 80 mL of HMPA to the dried flask. Stir to mix. Next, add 32 mL of chlorotrimethylsilane (equivalent to 0.24 mol). Stir the mixture for 90 minutes at room temperature. Cool the mixture on ice for 20 minutes. 

The conjugate addition of bis(iodozincio)methane to -unsaturated carbonyl compound gives y-zincio substituted enolate. As shown in equation 31, bis(iodozincio)methane reacts with. v-cis a,/3-unsaturated ketone in the presence of chlorotrimethylsilane to afford the silyl enol ether carrying a C—Zn bond. These zinc-substituted silyl enolates can be used for further coupling reactions (equation 32)54. 

The reactions lead to a low amount of bibenzyl, except when the aromatic ring is substituted by a methyl substituent in ortho or para position. The benzylic zinc species exhibit a high stability in acetonitrile and solutions can be stored for several days, at room temperature under argon atmosphere with no detectable damage of the organozinc. Despite this stability, these organozinc species can react with aromatic aldehyde and 3-thiophene aldehyde provided use is made of chlorotrimethylsilane, which is known to activate the carbonyl function (equation 22)29. 

Bicyclo[4.2.0]octanes wiLh carbonyl groups adjacent to each bridgehead carbon cleave the central bond on reduction with lithium in liquid ammonia,158,159 with sodium/potassium alloy in the presence of chlorotrimethylsilane,160 with zinc in acetic acid,37 or with zinc amalgam in hydrochloric acid.15 7... 

TrimethylsUylacetonitrile, (CH3)3SiCH2CN (1). Mol. wt. 113.24, b.p. 65-70°/20 mm. The reagent is readily obtained by reaction of chlorotrimethylsilane with bromo-acetonitrile in the presence of activated zinc (80% yield).1... 

As a good compromise between preformed zinc/copper couple which is very easy to prepare on large scale, but not especially reactive, and very reactive Rieke zinc, it is possible to activate commercially available zinc dust (Aldrich -325 mesh) by treatment first with 1,2-dibromoethane and then with chlorotrimethylsilane.7 This process, which is routinely carried out in situ, is a reliable and quick method for the preparation of zinc which is sufficiently reactive for many purposes. 

The realization that zinc dust can be activated by treatment, sequentially, with 1,2-dibromoethane and chlorotrimethylsilane, has had a significant impact on... 

Fiirstner reported the first McMurry-type reactions working with 5-10 mol% of titanium trichloride and stoichiometric amounts of zinc powder in the presence of chlorotrimethylsilane. The amount of TiCl3 could be reduced to 2 mol% when (ClMe2SiCH2)2 was used as a reagent [125, 131]. At the same time, Burton and coworkers reported atom transfer radical additions of perfluoroalkyl iodides 39 to alkenes 40 catalyzed by 20 mol% of a low-valent titanium compound generated from TiCLt and zinc powder affording 41 in 10-85% yield (Fig. 13). A tandem radical addition/5-exo cyclization/iodine transfer reaction with diallyl ether proceeded in 66% yield [132]. 

Zhou and Hirao showed that a low-valent catalyst generated from CP2VCI2 or VC12 and zinc in the presence of chlorotrimethylsilane is active in tandem reductive dimerization/Thorpe-Ziegler-type cyclizations of arylidenemalononitriles 96 (Fig. 29) [188]. The low-valent catalyst transfers an electron to 96 and the thus generated radical anion 96A adds to another molecule of 96. The resulting distonic... 

---