Chlorotrimethylsilane-Lithium

ALKYL BROMIDES Bromine. Bromo-triniethylsilane. Chlorotrimethylsilane-Lithium bromide. 

Triphenylphosphine-Diethyl azodicar-boxylate, 332 Other substitutions Allyltrimethylsilane, 11 Benzylamine, 79 Bromodimethylborane, 47 Chlorotrimethylsilane-Lithium, 81 Crotyltrimethylsilane, 86 Diethylzinc-Titanium(IV) chloride, 21 Lithium bis(dimethylphenylsily 1)-cuprate, 161... 

Allylic phosphorus compounds Tris(tetrabutylammonium) pyrophosphate, 338 Allylsilanes t-Butyllithium, 58 Chlorotrimethylsilane-Lithium, 81 Lithium bis(dimethylphenylsilyl)-cuprate, 161 Methyllithium, 188 Trichlorosilane-t-Amines, 322 Allylic sulfur compounds (Phenylsulfonyl)allene, 247 Sodium benzenesulfinate, 289... 

Cesium fluoride-Tetraalkoxysilanes, 69 Chlorodiisopropylsilane, 72 Chlorodimethylsilane, 73 Chlorodimethylthexylsilane, 74 Chlorodiphenylsilane, polymeric, 74 Chloromethyldiphenylsilane, 74 Chloromethyltrimethylsilane, 76 Chlorotriethylsilane, 165, 323 Chlorotrimethylsilane, 165, 168 Chlorotrimethylsilane-Lithium, 81 Chlorotrimethylsilane-Sodium iodide, 81... 

The synthesis of 2-trimethylsilyoxy-l,3-butadiene by treatment of methyl vinyl ketone with chlorotrimethylsilane, lithium bromide and triethylamine in tetrahydrofuran was discussed in section 12.5.6. It was discussed how the stoichiometry of the reaction was determined by canonical analysis of the response surface model, and how this analysis made it possible to establish experimental conditions which afforded a quantitative conversion. However, before the response surface model could be established it was necessary to find a reaction system worth optimizing. 

Preparative Methods the reaction of chlorotrimethylsilane, lithium metal, and chloroform in THE gives tris(trimethyl-silyl)methane. ... 

Substituted 2-butenylboranes 1 can be prepared via the metalation of 9-[(E)-2-butenyl]-9-borabicyclo[3.3.1]nonane with lithium tetramethylpiperidide (LTMP) in tetrahydrofuran at 23 "C followed by treating the resulting anion with chlorotrimethylsilane or chlorotrimethyl-slannanels. 

Silylnitronates 1 are prepared14-24,25 by metalation of primary nitroalkanes with lithium diisopropylamide and treatment of the lithionitronates with either chlorotrimethylsilane or (/er/-butyldimethyl)chlorosilane. Nonaqueous workup and distillation gives the silylnitronates in >75% yield as moisture sensitive, but thermally stable, products. (e/7-Butyldimethylsilylni-tronates are more stable than the corresponding trimethylsilyl compounds. 

The conjugate addition of lithium dimethylcuprate to spiroketone 5 gave predominantly (S j-6 [(S)/(R) 92 8] in which methyl group attacked from the side syn to the oxygen atom, whereas the addition of lithium dimethylcuprate-chlorotrimethylsilane afforded exclusively the anti-adduct (S)-621,... 

Reagents. n-butyl lithium (Koch-Light) was supplied as a solution in n-hexane (1.55 mol dm-J) and transferred to the reaction vessel via a suba-seal cap using a syringe. Chlorotrimethylsilane and trichloromethylsilane (Aldrich) were distilled under reduced pressure. Ammonia (BDH) was supplied as an "0.880" solution in water. 

A route involving trapping the enolate as a silyl enol ether, subsequent transme-tallation to the corresponding lithium enolate and alkylation turned out to be more efficient (Scheme 18.41) [123]. Thus, treatment of 120 with the cuprate 124 and chlorotrimethylsilane furnished the silyl enol ether 125, which was then converted into the desired enprostil derivative 127 with 68% yield over both steps by reaction with methyllithium and the allenic triflate 126. 

Organosilylphosphines are conveniently prepared by cleavage of alkyldiaryl-phosphines with lithium in THF, followed by treatment with chlorotrimethyl-silane,15 and tris(trimethylsilyl)phosphine has been prepared from the reaction of chlorotrimethylsilane with a mixture of sodium and potassium phosphides.16... 

MeOC6H4, respectively. The titanium enolates were converted into silyl enol ethers 54 by treatment with chlorotrimethylsilane and lithium isopropoxide. Additionally, cyclic enones lb and Ic, and linear enones Id and le, are also good substrates for the asymmetric conjugate addition of phenyltitanium triisopropoxide, giving the corresponding arylation products with over 97% enantioselectivity. 

The reaction of S,N (produced from S,NH and n-butyl-lithium in THF) with chlorotrimethylsilane at —60 C led to the exclusive formation of l,4-SgN2(SiMe3)2. McGlinchey and co-workers have proposed the following mechanism involving the... 

Disilathianes, for example (SiH3)2S and [(CH3)3Si] 2S, have been prepared by several routes, namely, the reaction of iodosilane with silver8 and mercuric2 sulfides halosilanes with lithium sulfide,7 [NH4]SH,9 and [Me3NH]SH7 disilaselenane with H2S10 and trisilylphosphine with sulfur.10 Recently, the synthesis of hexamethyldisilathiane, [(CH3)3Si] 2S, was described from the protolysis of l-(trimethylsilyl)imidazole with H2S and from the dehydrohalogen-ation of chlorotrimethylsilane and H2S with a tertiary amine.11 Both of these methods require about 18 hours. 

Substituted cyclohexanones, bearing a methyl, isopropyl, tert-butyl or phenyl group, give, on deprotonation with various chiral lithium amides in the presence of chlorotrimethylsilane (internal quench), the corresponding chiral enol ethers with moderate to apparently high enantioselec-tivity and in good yield (see Table 2)13,14,24> 29 36,37,55. Similar enantioselectivities are obtained with the external quench " technique when deprotonation is carried out in the presence of added lithium chloride (see Table 2, entries 5, 10, and 30)593. 

The feasibility of a deprotonation of cyclohexanone derivatives bearing a chiral heterocyclic substituent in the 4-position with the C2-symmetric base lithium bis[(/f)-l-phenylethyl]amide with internal quenching of the lithium enolate formed with chlorotrimethylsilane is shown in entries 32 and 33 of Table 229,25a. The silyl enol ethers are obtained in a diastereomeric ratio of 79.5 20.5. By using lithium bis[(1S)-l-phenylethyl]amide the two diastereomers are formed in a ratio of 20 80 indicating that the influence of the chirality of the substituent is negligible. 

Enantioselective deprotonation can also be successfully extended to 4,4-disubstituted cyclohexanones. 4-Methyl-4-phenylcyclohexanone (3) gives, upon reaction with various chiral lithium amides in THF under internal quenching with chlorotrimethylsilane, the silyl enol ether 4 having a quaternary stereogenic carbon atom. Not surprisingly, enantioselectivities are lower than in the case of 4-tm-butylcyclohexanone. Oxidation of 4 with palladium acetate furnishes the a./i-unsaturated ketone 5 whose ee value can be determined by HPLC using the chiral column Chiralcel OJ (Diacel Chemical Industries, Ltd.)59c... 

Enantioselective deprotonation of 4-(p-tolyl)-4-methyl cyclohexanone with lithium bis[(S)-l-phenylethyl]amide in THF at 100 C in the presence of chlorotrimethylsilane gives (R)-4-methyl-4-... 

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