Lithium hexamethyl disilazide

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... 

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. 

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