Scope and Mechanism of Direct Indole and Pyrrole Couplings Adjacent to Carbonyl Compounds: Total Synthesis of Acremoauxin A and Oxazinin 3

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• 作者：Jeremy M. Richter ; Brandon W. Whitefield ; Thomas J. Maimone ; David W. Lin ; M. Pilar Castroviejo ; Phil S. Baran
• 刊名：Journal of the American Chemical Society
• 出版年：2007
• 出版时间：October 24, 2007
• 年：2007
• 卷：129
• 期：42
• 页码：12857 - 12869
• 全文大小：317K
• 年卷期：v.129,no.42(October 24, 2007)
• ISSN：1520-5126

文摘

Full details are provided for a recently invented method to couple indoles and pyrroles to carbonylcompounds. The reaction is ideally suited for structurally complex substrates and exhibits high levels ofchemoselectivity (functional group tolerability), regioselectivity (coupling occurs exclusively at C-3 of indoleor C-2 of pyrrole), stereoselectivity (substrate control), and practicality (amenable to scaleup). In addition,quaternary stereocenters are easily and predictably generated. The reaction has been applied to a numberof synthetic problems including total syntheses of members of the hapalindole family of natural products,ketorolac, acremoauxin A, and oxazinin 3. Mechanistically, this coupling protocol appears to operate by asingle electron-transfer process requiring generation of an electron-deficient radical adjacent to a carbonylwhich is then intercepted by an indole or pyrrole anion.