Construction of quaternary carbon centers by a base-catalyzed enantioselective aldol reaction and related reactions of trimethoxysilyl enol ethers

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• 作者：Tomonori Ichibakase^a ; Tetsuya Kaneko^a ; Yuya Orito^a ; Shunsuke Kotani^b ; Makoto Nakajima^a ; ^{nakajima@gpo.kumamoto-u.ac.jp}
• 关键词：Aldol reaction ; Aldol-Tishchenko reaction ; Lithium binaphtholate ; Trimethoxysilyl enol ether
• 刊名：Tetrahedron
• 出版年：2012
• 期刊代码：107_00404020
• 类别：ch
• 出版时间：3 June, 2012
• 卷：68
• 期：22
• 页码：4210-4224
• 文件大小：1497 K

摘要

The aldol reactions of trimethoxysilyl enol ethers catalyzed by lithium binaphtholate were found to be powerful tools for the construction of quaternary asymmetric carbon centers. The stereoselectivities were greatly affected by the presence of water. Trimethoxysilyl enol ether derived from a cyclic ketone, such as cyclohexanone, was used as a substrate to obtain the anti-adduct preferentially under anhydrous conditions; by contrast, the syn-adduct was preferentially obtained under aqueous conditions with high stereoselectivity. The aldol-Tishchenko reaction of a trimethoxysilyl enol ether derived from acyclic ketones proceeded to give monoacyl 1,3-diol derivatives in high enantioselectivities.