CHEMISTRY OF CARBANIONS .18. PREPARATION OF TRIMETHYLSILYL ENOL ETHERS

Two procedures for the preparation of trimethylsilyl enol ethers from aldehydes and ketones are described. Reaction of the ketone with chlorotrimethylsilane and triethylamine in dimethylformamide solution usually affords an equilibrium mixture of the trimethylsilyl enol ethers. Successive reaction of the ketone with lithium di-isopropylamide and with chlorotrimethylsilane in 1,2-dimethoxyethane solution normally produces a mixture in which the less highly substituted enol ether (from kinetically controlled enolate formation) is the principal product. A number of representative structurally and stereochemicaly isomeric trimethylsilyl enol ethers have been characterized (see Table II) and their physical properties have been studied. © 1969, American Chemical Society. All rights reserved.