First Total Synthesis of the Cytotoxic Carbazole Alkaloid Excavatine‐A and Regioselective Annulation to Pyrano[2,3‐<i>a</i>]carbazoles and [1,4]Oxazepino[2,3,4‐<i>jk</i>]carbazoles
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- Christian Brütting
- Department Chemie Technische Universität Dresden Bergstraße 66 01069 Dresden Germany
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- Olga Kataeva
- A. M. Butlerov Chemistry Institute Kazan Federal University Kremlevskaya Str. 18 420008 Kazan Russia
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- Arndt W. Schmidt
- Department Chemie Technische Universität Dresden Bergstraße 66 01069 Dresden Germany
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- Hans‐Joachim Knölker
- Department Chemie Technische Universität Dresden Bergstraße 66 01069 Dresden Germany
抄録
<jats:p>We describe the first total synthesis of the cytotoxic carbazole alkaloid excavatine‐A. The carbazole framework was constructed through double C–H bond activation of a diarylamine by using our palladium(II)‐catalyzed oxidative cyclization. Treatment of the intermediate 8‐hydroxycarbazoles with prenal and different additives led either to pyrano[2,3‐<jats:italic>a</jats:italic>]carbazoles or to [1,4]oxazepino[2,3,4‐<jats:italic>jk</jats:italic>]carbazoles. The pyran annulation was investigated to determine the influence of substitution pattern, additives, and reaction time on the selectivity.</jats:p>
収録刊行物
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- European Journal of Organic Chemistry
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European Journal of Organic Chemistry 2017 (22), 3288-3300, 2017-06-14
Wiley