Exo Selective Enantioselective Nitrone Cycloadditions

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• 作者：Mukund P. Sibi ; Zhihua Ma ; and Craig P. Jasperse
• 刊名：Journal of the American Chemical Society
• 出版年：2004
• 出版时间：January 28, 2004
• 年：2004
• 卷：126
• 期：3
• 页码：718 - 719
• 全文大小：58K
• 年卷期：v.126,no.3(January 28, 2004)
• ISSN：1520-5126

文摘

We have developed a novel method for accessing exo adducts with high enantioselectivity in nitrone cycloadditions to enoates. Pyrazolidinones proved to be effective achiral templates in the cycloadditions, providing exo adducts typically in >15:1 selectivity and 90-98% ee. The use of Lewis acids that form square planar complexes, such as copper triflate, was important for obtaining high exo selectivity.