An Essentially Mild and Efficient Catalyst System for the Activation of Carbonyl Compounds and Their Derivatives. The Combined Use of Trimethylsilyl Chloride and Tin(II) Chloride
作者:Nobuharu Iwasawa、Teruaki Mukaiyama
DOI:10.1246/cl.1987.463
日期:1987.3.5
An essentially mild and efficient catalyst system, the combined use of trimethylsilyl chloride and tin(II) chloride, is effectively employed for the activation of acetals, aldehydes, orthoesters, and α,β-unsaturatedketones to accomplish the reaction with silyl enolethers to give the corresponding addition products in good yields.
In the presence of a catalytic amount of trityl perchlorate, 1,5-dicarbonyl compounds, the Michael adducts, are obtained in high yields by the reaction of silyl enol ethers with α,β-unsaturated ketones. The intermediate adducts, the synthetically valuable silyl enol ethers, are also isolated in high yields.
A Convenient Method for the Preparation of Secondary Propargylic Ethers. The Reactions of Acetals with 1-Trimethylsilyl-1-alkynes Promoted by the Combined Use of Catalytic Amounts of Tin(IV) Chloride and Zinc Chloride
SnCl4 and ZnCl2, acetals undergo a coupling with 1-trimethylsilylalkynes to give secondary propargylic ethers in good yields. Similarly, propargylic ethers are directly produced from aldehydes by the treatment with alkoxytrimethylsilanes and 1-trimethylsilylalkynes under the same conditions. This catalyst system also efficiently promotes aldol reaction of silylenolethers with acetals or aldehydes, and