Lithium, 1,1,1,3,3,3-hexamethyl-2-

The systematic names for these compounds are lithium 1,1,1,3,3,3-hexamethyl-2-(trimethyl-silyl)-2-trisilanetellurolate-bis(tetrahydrofuran) and 1,1,1,3,3,3-hexamethyl-2-(trimethylsilyl)-2-trisilanetellurol. 

Deprotonation of / /-cyclohexylfluoroacetone imines by lithium hexamethyl-disilazide or tertiary butyl lithium at very low temperature allows a regioselective alkylation at the carbon carrying fluorine [773] (equation 98). 

Lithium cyclohexylisopropylamide Lithium diisopropylamide Lithium hexamethyl disilazide Lithium 2,2,6,6-tetramethylpiperidide Methylaluminum I ij-(4-bromo-2,6-di-tert-butylphenoxide) I (s-(2,6-di-t-butyl-4-methylphenoxy)methyl aluminum mefa-Chloroperoxybenzoic acid Methyl... 

Mukaiyama found that Lewis acids can induce silyl enol ethers to attack carbonyl compounds, producing aldol-like products.22 The reaction proceeds usually at -78 °C without selfcondensation and other Lewis acids such as TiCl4 or SnCI4 are commonly used. The requisite silyl enol ether 27 was prepared by treatment of ketone 13 with lithium hexamethyl disilazide (LiHMDS) and trapping the kinetic enolate with chlorotrimethylsilane. When the silyl enol ether 27 was mixed with aldehyde 14 in the presence of BF3-OEt2 a condensation occurred via transition state 28 to produce the product 29 with loss of chlorotrimethylsilane. The induced stereochemistry in Mukaiyama reactions using methylketones and a, -chiral aldehydes as substrates... 

Lithio-l,3-dithiane and 2-lithio-l,3,5-trithiane have been transformed into 2-substituted benzylamines 273 and 274, respectively, by reaction with a mixture of benzaldehyde and lithium hexamethyl disilazide449. In the case of compound 266, the corresponding derivatives 275 and 276 have also been prepared. Related compounds were used for the preparation of photolabile molecular hosts. 

Freshly prepared LDA has varying stability, being most stable in alkanes and 1 1 aIkanes THF. Homemade LDA should be stored cold to extend its shelf-life. The preparation of LDA is representative of other lithium amide bases, such as lithium tetramethylpiperidide and lithium hexamethyl disilylamide. 

Tris[methyl(trimethylsilyl)amino]bismuthine Bi[N(Me)SiMc3]3 is prepared in 54% yield by the reaction of BiBr3 with the corresponding lithium amide in hexane. This compound can be distilled under reduced pressure [66JOM(6) 259]. Similarly, tris[bis(trimethylsilyl)amino]bismuthine Bi[N(SiMe3)2]3 is obtained as a pale yellow powder by treating BiCl3 with lithium hexamethyl-... 

The dimethyl tartrate derivative (144) forms the dilithium salt (145) with excess lithium hexamethyl-disilazane and this smoothly transforms into the butenolide (146), which is obtained crystalline in 78% yield.Lithiation of the hydroxy group prevents 1,2-elimination (Scheme 44). 

Hexamethylphosphoramide (Me3N)3P=0 Hexamethylphorous triamide (Me3N)3P Isopropyl — CH(CH3)2 Lithium cyclohexylisopropylamide Lithium diisopropylamide LiN(iPr)2 Lithium hexamethyl disilazide LiN(SiMe3)2 Lithium 2,2,6,6-tetramethylpiperidide meta-Chloroperoxybenzoic acid Methyl — CH3... 

Related Reagents. Lithium Amide Lithium Hexamethyl-disilazide Lithium Diethylamide Lithium Piperidide Lithium Pyrrolidide Lithium 2,2,6,6-tetramethylpiperidide Potassium Diisopropylamide. 

Recently, we have studied the addition of organometallic compounds to aluminum-imines and silylimines which are easily prepared from nitriles and aldehydes ly treatment with diisobutyl aluminum hydride (DIBAH) and lithium hexamethyl disilyl... 

Benzoylmethylenetriphenylphosphorane allowed to react with lithium-hexamethyl-phosphoramide in benzene, then with 4-heptanone -> product. Y 52%. F. e. s. C. Broquet and M. Simalty, Tetrah. Let. 1972, 933. 

Simultaneous elimination of chloride ion and carbon dioxide occurs dunng heating of methyl chlorodifluoroacetate with lithium chloride in hexamethyl-phosphoric tnamide (HMPA) The difluorocarbene generated in this way is trapped by electron-rich alkenes to form 1,1-difluorocyclopropanes [26] (equation 24)... 

HYPHAT Bis(tetrachlorobenzenediolato)mono(l,2-diarylethanediolato)phosphate(v) LiHMDS Lithium l,l,l,3>3,3-hexamethyl-disilazane... 

Various alkyl- and aryl-substituted [3]radialenes could be prepared from 1,1-dihaloal-kenes using organometallic pathways. Hexamethyl-[3]radialene (25), the first [3]radialene to be synthesized, was obtained in a very low yield by treatment of l,l-dibromo-2-methyl-1-propene (22) with butyllithium8,9. The lithium carbenoid 23 and the butatriene 24 are likely intermediates of this transformation (Scheme 2), the former being the source of an unsaturated carbene moiety which is transferred onto the latter. However, the outer double bonds of 24 are more readily cyclopropanated than the central one. 

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