Enantioselective 2-Alkylation of 3-Substituted Indoles with Dual Chiral Lewis Acid/Hydrogen-Bond-Mediated Catalyst

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• 作者：Zijun Zhou ; Yanjun Li ; Lei Gong ; Eric Meggers
• 刊名：Organic Letters
• 出版年：2017
• 出版时间：January 6, 2017
• 年：2017
• 卷：19
• 期：1
• 页码：222-225
• 全文大小：434K
• ISSN：1523-7052

文摘

A chiral-at-metal bis-cyclometalated iridium complex combines electrophile activation via metal coordination with nucleophile activation through hydrogen bond formation. This new bifunctional chiral Lewis acid/hydrogen-bond-mediated catalyst permits the challenging enantioselective 2-alkylation of 3-substituted indoles with α,β-unsaturated 2-acyl imidazoles in up to 99% yield and with up to 98% enantiomeric excess at a catalyst loading of 2 mol %. As an application, the straightforward synthesis of a chiral pyrrolo[1,2-a]indole is demonstrated.