Ketene t-butyldimethylsilyl methyl acetal

SILYLATION Bis(trimethylsilyl)urea. t-Butyldimethylchlorosilane. t-Butyldimethylsilyl trifluoromethanesulfonate. Chlorotrimethylsilane. Dimethyl(2,4,6-tri-f-butylphenoxy)chlorosilane. Ethyl trimethylsilylacctate. Ketene t-butyldimethylsilyl methyl acetal. N-Methyl-N-(/-... 

Related Reagents. For comparison and more details, see also those entries that deal with other silyl ketene acetals, in particular 1-f-butylthio-l-f-butyldimethylsilyloxypropene, ketene t-butyldimethylsilyl methyl acetal, and analogs. 

Related Reagents. t-Butyl a-Lithiobis(lrimethylsilyl)acetate t-Butyl Trimethylsilylacetate Dilithioacetate Ethyl Bromozin-cacetate Ethyl Lithioacetate Ethyl Lithio(trimethylsilyl)acetate Ketene Bis(trimethylsilyl) Acetal Ketene t-Butyldimethylsilyl Methyl Acetal l-Methoxy-2-trimethylsilyl-l-(trimethylsilyloxy)-ethylene Methyl (Methyldiphenylsilyl)acetate Trimethylsilyl-acetic Acid. 

Related Reagents. t-Butyl a-Lithioisohutyrate Dilithio-acetate Ethyl Lithioacetate Ketene Bis(trunethylsilyl) Acetal Ketene f-Butyldimethylsilyl Methyl Acetal l-Methoxy-l-(tri-methylsilyloxy)propene l-Methoxy-2-trunethylsilyl-l-(tri-methylsilyloxy)ethylene Tris(trimethylsilyloxy)ethylene. 

Ketene silyl acetals. The enolsilylation of esters is highly dependent on the bases used. Contrasting stereoselectivities in the silylation of methyl a-f-butyldi-methylsiloxyacetate are found with respect to the reaction conditions The ( )-isomer is obtained in the trimethylsilylation promoted by lithium tetramethylpiperidide, and the (Z)-isomer from the reaction with t-butyldimethylsilyl chloride in the presence of LHMDS and HMPA. 

Benzylamino-2-(trimethylsilylmethyl)-but-l-ene cyclizes in the presence of acid to afford the azepine (138) <86TL5067>, and 7V-benzyl-6-(phenylsulfinyl)-hexanamide reacts with O-methyl-O-t-butyldimethylsilyl ketene acetal to afford the lactam (139) <90CPB1473>. Direct irradiation of ortho-(A -methylaminoethyl)stilbene in acetonitrile affords Af-methyl-2-phenyl-2,3,4,5-tetrahydro-benz[primary product but which undergoes demethylation upon further irradiation <92TL4249>. The demethylated product may also be obtained by irradiation of o-(3-amino-n-propyl)stilbene in the presence of w-dicyanobenzene as electron transfer agent. 

A new and efficient combination for silylation is trimethylsilyl chloride-lithium sulphide. Even hindered hydroxy-groups are silylated at room temperature in neutral conditions, although the mechanism of the process is not yet clear. 4-Dimethylaminopyridine (DMAP) has been shown to be an efficient catalyst for the silylation of alcohols by t-butyldimethylsilyl chloride and to be more selective than the imidazole traditionally used. Two new methods for removal of the t-butyldimethylsilyl group are treatment with boron trifluoride etherate and reaction with aqueous HF in acetonitrile. The O-silyl derivatives of normal carboxylic esters, i.e. keten methyl trialkylsilyl acetals (59), have been investigated in silyl transfer to alcohols (Scheme 31) they have the advantage of... 

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See also in sourсe #XX -- [ ]

See also in sourсe #XX -- [ , , , ]

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