Transannular Diels鈥揂lder/1,3-Dipolar Cycloaddition Cascade of 1,3,4-Oxadiazoles: Total Synthesis of a Unique Set of Vinblastine Analogues

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• 作者：Erica L. Campbell ; Colin K. Skepper ; Kuppusamy Sankar ; Katharine K. Duncan ; Dale L. Boger
• 刊名：Organic Letters
• 出版年：2013
• 出版时间：October 18, 2013
• 年：2013
• 卷：15
• 期：20
• 页码：5306-5309
• 全文大小：330K
• 年卷期：v.15,no.20(October 18, 2013)
• ISSN：1523-7052

文摘

A powerful tandem [4 + 2]/[3 + 2] cycloaddition cascade of 1,3,4-oxadiazoles initiated by a transannular [4 + 2] cycloaddition is detailed. An impressive four rings, four carbon鈥揷arbon bonds, and six stereocenters are set on each site of the newly formed central six-membered ring in a cascade thermal reaction that proceeds at temperatures as low as 80 掳C. The resulting cycloadducts provide the basis for the synthesis of unique analogues of vinblastine containing metabolically benign deep-seated cyclic modifications at the C3/C4 centers of the vindoline-derived subunit of the natural product.