Stereochemistry and Mechanism of the Ring-Opening Reaction of Cyclopropylenones with LiCu(Me)2

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• 作者：Charles P. Casey ; Mark C. Cesa ; Alan J. Shusterman
• 刊名：Organometallics
• 出版年：2012
• 出版时间：November 26, 2012
• 年：2012
• 卷：31
• 期：22
• 页码：7849-7854
• 全文大小：323K
• 年卷期：v.31,no.22(November 26, 2012)
• ISSN：1520-6041

文摘

The chemical shifts of the diastereotopic hydrogens of the ethyl group of the cyclopropane ring-opening product of conjugate addition of LiCu(CH₃)₂ to cyclopropyl enone 1 were computed. Comparison of computed and observed p>1p>H NMR chemical shifts of the diastereotopic hydrogens of the ethyl group of 2 established the stereochemistry of the ring-opening product as 2d-b. This provides evidence that the reaction proceeds by conjugate addition of the cuprate to the enone, followed by ring-opening of the cyclopropylmethyl copper species and reductive elimination.