Concise, Enantioselective, and Versatile Synthesis of (−)-Englerin A Based on a Platinum-Catalyzed [4C+3C] Cycloaddition of Allenedienes

详细信息    查看全文

• 作者：Ronald Nelson ; Dr. Moisé ; s Gulí ; as ; Prof. José ; L. Mascare&ntilde ; as and Dr. Fernando L&oacute ; pez
• 刊名：Angewandte Chemie
• 出版年：2016
• 出版时间：November 7, 2016
• 年：2016
• 卷：128
• 期：46
• 页码：14571-14575
• 全文大小：943K
• ISSN：1521-3757

文摘

A practical synthesis of (−)-englerin A was accomplished in 17 steps and 11 % global yield from commercially available achiral precursors. The key step consists of a platinum-catalyzed [4C+3C] allenediene cycloaddition that directly delivers the trans-fused guaiane skeleton with complete diastereoselectivity. The high enantioselectivity (99 % ee) stems from an asymmetric ruthenium-catalyzed transfer hydrogenation of a readily assembled diene–ynone. The synthesis also features a highly stereoselective oxygenation, and a late-stage cuprate alkylation that enables the preparation of previously inaccessible structural analogues.