The aldol reaction of silyl enol ethers with acetals or aldehydes, and the Michael reaction of silyl enol ethers with α,β-unsaturated ketones are efficiently catalyzed by the combined use of trityl chloride and tin(II) chloride under extremely mild conditions.
甲硅烷基烯醇醚与缩醛或醛的羟醛反应,以及甲硅烷基烯醇醚与 α,β-不饱和酮的迈克尔反应通过三苯甲基氯和氯化锡 (II) 的联合使用在极其温和的条件下有效催化。
Lithium Alkoxide-promoted Michael Reaction between Silyl Enolates and α,β-Unsaturated Carbonyl Compounds
Michael reactionbetween silyl enolates and 0',/3-unsaturated carbonyl compounds by using a catalytic amount of Lewis base such as lithium alkoxide in DMF proceeds smoothly to afford the corresponding Michael-adducts in good yields with moderate to high diastereoselectivities. This reaction can be reasonably explained by considering an alkoxide anion-initiated autocatalytic process.
Novel reactive silyl enolates. Highly stereoselective aldol and Michael reactions without catalysts
作者:Shu Kobayashi、Koichi Nishio
DOI:10.1021/jo00062a002
日期:1993.5
Novel silyl enolates, prepared in situ from ketones and dimethylsilyl ditriflate (Me2Si(OTf)2) in the presence of a tertiary amine, reacted smoothly with electrophiles such as aldehydes, acetals, or alpha,beta-unsaturated ketones without catalyst at -78-degrees-C to afford the corresponding adducts in high yields and with high selectivities.