Stereoselective Synthesis of Isoquinuclidines through an Aza-[4 + 2] Cycloaddition of Chiral Cyclic 2-Amidodienes

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• 作者：Li-Chao Fang ; Richard P. Hsung
• 刊名：Organic Letters
• 出版年：2014
• 出版时间：March 21, 2014
• 年：2014
• 卷：16
• 期：6
• 页码：1826-1829
• 全文大小：370K
• 年卷期：v.16,no.6(March 21, 2014)
• ISSN：1523-7052

文摘

A highly stereoselective aza-[4 + 2] cycloaddition of chiral cyclic 2-amidodienes with N-sulfonyl aldimines is described. While this Lewis acid promoted heterocycloaddition provides an efficient strategy for constructing optically enriched isoquinuclidines, it is mechanistically intriguing. The cycloaddition favored the endo-II pathway in the absence of a viable bidentate coordination. This represents an unexpected switch from the anticipated endo-I selectivity obtained in the all-carbon cycloaddition.