Unexpected ambidoselectivity in crossed-aldol reactions of α-oxy aldehyde trichlorosilyl enolates

被引：11

作者：

Denmark, Scott E. ^{[1
]}

Ghosh, Sunil K. ^{[1
]}

机构：

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

来源：

TETRAHEDRON | 2007年 / 63卷 / 35期

基金：

美国国家科学基金会;

关键词：

aldol enolate; deuterium labeling; enantioselective; diastereoselective;

D O I：

10.1016/j.tet.2007.04.009

中图分类号：

O62 [有机化学];

学科分类号：

070303 ; 081704 ;

摘要：

The ambido-, stereo- and enantioselectivity of the phosphoramide-promoted aldol reactions of alpha-oxy aldehyde trichlorosilyl enolates with benzaldehyde has been investigated. Analysis of the products from alpha-tert-butyldimethylsilyloxy alpha-deuterioacetaldehyde trichlorosilyl enolate confirmed that this 1,2-bis-silyloxyethene derivative reacted as a tert-butyldimethylsilyl enolate rather than trichlorosilyl enolate in the aldol reaction with very high ambidoselectivity. The phosphoramide-coordinated trichlorosilyl group acted as an organizing center for the aldol reaction. From the aldol process, excellent anti-diastereoselectivity could be achieved. The enantioselectivity remained moderate to low for both anti- and syn-diastereomer with a wide range of phosphoramide catalysts. alpha-Triisopropylsilyloxy, phenoxy and benzyloxy acetaldehyde trichlorosilyl enolates also reacted in a similar fashion with benzaldehyde to give aldol products with varying degrees of selectivities. (c) 2007 Elsevier Ltd. All rights reserved.

引用

页码：8636 / 8644

页数：9

共 43 条

[11] Lewis base activation of Lewis acids: Catalytic, enantioselective addition of silyl ketene acetals to aldehydes [J].

Denmark, SE ;

Beutner, GL ;

Wynn, T ;

Eastgate, MD .

JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 2005, 127 (11) :3774-3789

[12] Chiral phosphoramide-catalyzed, enantioselective, directed cross-aldol reactions of aldehydes [J].

Denmark, SE ;

Bui, T .

PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 2004, 101 (15) :5439-5444

[13] Lewis base activation of Lewis acids. Vinylogous aidol reactions [J].

Denmark, SE ;

Beutner, GL .

JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 2003, 125 (26) :7800-7801

[14]

Denmark SE, 2001, ANGEW CHEM INT EDIT, V40, P4759, DOI 10.1002/1521-3773(20011217)40:24<4759::AID-ANIE4759>3.0.CO

[15]

2-G

[16] Lewis base activation of Lewis acids: Catalytic enantioselective allylation and propargylation of aldehydes [J].

Denmark, SE ;

Wynn, T .

JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 2001, 123 (25) :6199-6200

[17] The chemistry of chlorosilyl enolates. 9. Preparation of chlorosilyl enolates [J].

Denmark, SE ;

Stavenger, RA ;

Winter, SBD ;

Wong, KT ;

Barsanti, PA .

JOURNAL OF ORGANIC CHEMISTRY, 1998, 63 (25) :9517-9523

[18] Chiral phosphoramide-catalyzed aldol additions of ketone enolates. Preparative aspects [J].

Denmark, SE ;

Stavenger, RA ;

Wong, KT ;

Su, XP .

JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1999, 121 (21) :4982-4991

[19] The chemistry of trichlorosilyl enolates. Aldol addition reactions of methyl ketones [J].

Denmark, SE ;

Stavenger, RA .

JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 2000, 122 (37) :8837-8847

[20] Asymmetric catalysis of aldol reactions with chiral Lewis bases [J].

Denmark, SE ;

Stavenger, RA .

ACCOUNTS OF CHEMICAL RESEARCH, 2000, 33 (06) :432-440

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