Lewis base catalyzed aldol additions of chiral trichlorosilyl enolates and silyl enol ethers

被引：37

作者：

Denmark, SE ^{[1
]}

Fujimori, S ^{[1
]}

Pham, SM ^{[1
]}

机构：

[1] Univ Illinois, Dept Chem, Roger Adams Lab, Urbana, IL 61801 USA

来源：

JOURNAL OF ORGANIC CHEMISTRY | 2005年 / 70卷 / 26期

关键词：

D O I：

10.1021/jo051930+

中图分类号：

O62 [有机化学];

学科分类号：

070303 ; 081704 ;

摘要：

The consequences of double diastereodifferentiation in chiral Lewis base catalyzed aldol additions using chiral enoxysilanes derived from lactate, 3-hydroxyisobutyrate, and 3-hydroxybutyrate have been investigated. Trichlorosilyl enolates derived from the chiral methyl and ethyl ketones were subjected to aldolization in the presence of phosphoramides, and the intrinsic selectivity of these enolates and the external stereoinduction from chiral catalyst were studied. In the reactions with the lactate derived enolate, the strong internal stereoinduction dominated the stereochemical outcome of the aldol addition. For the 3-hydroxyisobutyrate- and 3-hydroxybutyrate derived enolates, the catalyst-controlled diastereoselectivities were observed, and the resident stereogenic centers exerted marginal influence. The corresponding trimethylsilyl enol ethers were employed in SiCl4/bisphosphoramide catalyzed aldol additions, and the effect of double diastereodifferentiation was also investigated. The overall diastereoselection of the process was again controlled by the strong external influence of the catalyst.

引用

页码：10823 / 10840

页数：18

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