Y. Yamamoto et C. Matui, PREPARATION OF SILYL ENOL ETHERS BY THE REACTION OF KETONES WITH SILYLAMINES AND METHYL-IODIDE, Organometallics, 16(10), 1997, pp. 2204-2206
Transformation of ketones to silyl enol ethers using (trimethylsilyl)d
iethylamine and methyliodide is described. Both cyclic and acyclic ket
ones gave silyl enol ethers in high yield, whose stereochemistry showe
d that the formation of thermodynamically stable isomers was favored.
A cyclic diketone, 1,4-cyclohexanedione, gave a 1:1 mixture of 1,4-bis
((trimethylsilyl)oxy)-1,3-cyclohexadiene and 1,4-bis((trimethylsilyl)o
xy)-1,3-cyclohediene, while 1,3-cyclohexanedione gave 3-((trimethylsil
yl)oxy)-2-cyclohexenone alone. The tert-butyldimethylsilyl enol ethers
of ketones also were obtained in high yield when (tert-butyldimethyls
ilyl)diethylamine, combined with methyl iodide, was used. A combinatio
n of allyl bromide and (trimethylsilyl)diethylamine was also effective
for the transformation of ketones to silyl enol ethers.