ketene bis(trialkylsilyl) acetals: synthesis, pyrolysis and spectral studies
作者:C. Ainsworth、Yu-Neng Kuo
DOI:10.1016/s0022-328x(00)90476-5
日期:1972.12
methods are described for the preparation of alkyl, dialkyl, aryl and diaryl ketene bis(trialkylsilyl)acetals. One is by reaction of αmetalated trimethylsilyl carboxylates with trimethylchlorosilane (TMCS) and the otehr is by inteaction of dianions of carboxylic acids and TMCS. The dianion of cyclopropane carboxylic acid and TMCS gave C-silated ester in 90% yield. Pyrolysis of diphenyl ketene bis(trialkylsilyl)
Metal reductions of malonates and oxalates. A covenient decarboxylation route for disubstituted malonates and synthesis of keten acetals
作者:Yu-Neng Kuo、Francis Chen、C. Ainsworth、Jordan J. Bloomfield
DOI:10.1039/c29710000136
日期:——
Alkali-metal reduction of disubstituted malonates or treatment of esters with base in the presence of trimethylchlorosilane gives high yields of the reactive disubstituted keten alkyl trimethylsilyl acetals, while diethyl oxalate, under similar conditions is reduced to 1,2-diethyl-1,2-bis(trimethylsilyloxy)ethylene.
of silyl enol ethers with simple chiral Brønsted acids, mainly due to bond flexibility between the proton and its chiral counterion, the orientational flexibility of the proton, and the fact that the proton sources available are limited to acidic compounds such as chiral carboxylic acids. To overcome these difficulties, we have developed a Lewis acid-assisted chiral Brønsted acid (LBA) system. The coordination
Enantioselective Protonation of Silyl Enol Ethers and Ketene Disilyl Acetals with Lewis Acid-Assisted Chiral Brønsted Acids: Reaction Scope and Mechanistic Insights
Enantioselectiveprotonation is a potent and efficient way to construct chiral carbons. Here we report details of the reaction usingLewisacid-assisted chiral Bronsted acids (chiral LBAs). The 1:1 coordinate complex of tin tetrachloride and optically active binaphthol ((R)- or (S)-BINOL) can directly protonate various silylenolethers and ketene disilyl acetals to give the corresponding α-aryl ketones
Lactones from lactones: a cascade transformation is observed during two successive double nucleophilic additions of bis (TMS) ketene acetals to pyridines.