T-Butoxide-catalysed condensation

Aryltrimethylsilanes also undergo a t-butoxide-catalysed condensation (9) with electrophiles, such as aldehydes ... 

Bromophenyl trimethylsilyl ether, 41 a-Bromovinyl(triphenyl)silane, 69 Brook rearrangement, 83-4 t-Butoxide-catalysed condensation, 43 ( )-4-t-Butyl-l-(trimethylsilyloxy)-... 

The compounds (250) and (251), synthesized by addition of azidoacetyl chloride to the appropriate thiazoline derivatives in the presence of tri-ethylamine, were converted by conventional procedures into structural isomers of penicillins, whilst the t-butoxide-catalysed condensation of... 

Al)-Acetyl-(A6)-aroyl-2,5-dithio-3,4,7,8-tetramethylglycolurils (92) and related compounds undergo a t-butoxide-catalysed Claisen-type condensation.268 Rate constants have been measured for the template-directed process, Hammett plots have been constructed, and deuterium isotope effects measured at the acetyl group. The... 

The condensation of aldehydes with thiocyanoacetic esters, catalysed by potassium fluoride or potassium carbonate, gave as minor products yV-carbamoyl-2-imino-5-alkyl(or aryl)-l, 3-oxathiolan-4-carboxylic esters, in which the 4,5-c/j-isomers predominated according to n.m.r. spectroscopy. l,3-Oxathiolan-2-thione was converted into dimethyl 1,3-dithiol-2-one-4,5-dicarboxylate and ethylene on treatment with dimethyl acetylene-dicarboxylate, and the transformation of methyl 2-methoxycarbonyl-methyl-1,3-oxathiolan-2-carboxylate into dimethyl-5,6-dihydro-l, 4-oxa-thiin-2,3-dicarboxylate by chlorination at low temperatures found analogy in the reactions of 2,2-dialkyl-l,3-oxathiolans. Thiomethoxymethyl hexachloroantimonate reacted with potassium t-butoxide to give mainly 3,5,5-trimethyl-l,3-oxathiolanium hexachloroantimonate the mechanism of this remarkable reaction was not settled. ... 

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