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Stereoselective formation of silylketene acetals from esters and trialkylsilyl perchlorates.

✍ Scribed by Craig S. Wilcox; Robert E. Babston

Publisher
Elsevier Science
Year
1984
Tongue
French
Weight
212 KB
Volume
25
Category
Article
ISSN
0040-4039

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✦ Synopsis

Alkanoate esters react with triethylsilyl perchlorate and trialkylamines at low temperature to yield 0-silylketene acetals. The 2 isomer is obtained in excellent yield.

1

Silylketene acetals find frequent application in carbon-carbon bond forming reactions.

One approach to silylketene acetals has involved ester deprotol;ation with a very strong base followed by silylation, usually with a trialkylsilyl chloride.

Simchen and Emde have successfully used trimethylsilyl triflate for preparing selected silylketene acetals, but for 3 propanoates and other alkanoates, their process provides the o-silyl esters.

We report here a new procedure for preparing Z-silylketene acetals from simple alkanoate esters and triethylsilyl perchlorate in high yield under kinetic conditions and requiring no strong base.

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