TfNH2 as Achiral Hydrogen-Bond Donor Additive to Enhance the Selectivity of a Transition Metal Catalyzed Reaction. Highly Enantio- and Diastereoselective Rhodium-Catalyzed Cyclopropanation

详细信息    查看全文

• 作者：David Marcoux ; Soula Azzi ; Andr B. Charette
• 刊名：Journal of the American Chemical Society
• 出版年：2009
• 出版时间：May 27, 2009
• 年：2009
• 卷：131
• 期：20
• 页码：6970-6972
• 全文大小：179K
• 年卷期：v.131,no.20(May 27, 2009)
• ISSN：1520-5126

文摘

A highly stereoselective (up to 98% ee and 99:1 dr) Rh(II)-catalyzed formation of nitrile-substituted cyclopropanes is described. α-Cyano diazoacetamide reagents react with a variety of mono- and disubstituted olefins in good yields and excellent enantio- and diastereocontrol. Less reactive substrates, such as aliphatic olefins, also undergo the reaction. This new methodology features the unprecedented use of an achiral hydrogen-bond donor additive to enhance the selectivity and exploits the powerful trans-directing ability of amides solving the diastereocontrol issue of the formation of substituted 1-cyanocyclopropane-1-carboxy derivatives.