Catalytic Enantioselective Alkylations of Tetrasubstituted Olefins. Synthesis of All-Carbon Quaternary Stereogenic Centers through Cu-Catalyzed Asymmetric Conjugate Additions of Alkylzinc Reagents to

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• 作者：Alexander W. Hird and Amir H. Hoveyda
• 刊名：Journal of the American Chemical Society
• 出版年：2005
• 出版时间：November 2, 2005
• 年：2005
• 卷：127
• 期：43
• 页码：14988 - 14989
• 全文大小：200K
• 年卷期：v.127,no.43(November 2, 2005)
• ISSN：1520-5126

文摘

A method for Cu-catalyzed asymmetric conjugate addition (ACA) of dialkylzinc reagents to tetrasubstituted five- and six-membered cyclic enones that afford quaternary all-carbon stereogenic centers in up to 95% ee is reported. Catalytic ACAs are practical and efficient. Reactions proceed to >98% conversion in undistilled commercial grade toluene in the presence of 2 mol % of an air-stable Cu salt (CuCN) and a readily available chiral ligand. Enantioselective ACA reactions deliver products that can be readily functionalized to afford a variety of synthetically versatile compounds in high optical purity.