- Indole-2,3-quinodimethanes: A New Strategy for the Synthesis of Tetracyclic Systems of Indole Alkaloids
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The imine 7, derived from N--2-methylindole-3-carboxaldehyde (6) and 4-pentenylamine, on treatment with a range of chloroformates gave cis-octahydropyridocarbazoles 8, in yields ranging from 43 to 92percent.Similarly the series of imines 18-24 derived from 6 and the corresponding amine gave, on treatmnt with the mixed carbonyc anhydride from ethyl chloroformate and 4-pentenoic acid 25, the tetracyclic amides 26-31.The equivalent series of transformations with a 4a-ethyl group present leads directly to cis-fused tetracyclic precursors 40-42 and 45.The structure and relative stereochemistry of the tetracyclic carbamate 43 is confirmed by single-crystal X-ray crystallography.Some general examples of indole-2,3-quinodimethane cyclizations that give fused pentacyclic and spirocyclic compounds 49, 50, and 51 directly are described.
- Exon, Christopher,Gallagher, Timothy,Magnus, Philip
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p. 4739 - 4749
(2007/10/02)
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- NEW METHODS FOR ALKALOID SYNTHESIS. GENERATION OF INDOLE-2,3-DIQUINOMETHANES AS A ROUTE TO INDOLE ALKALOIDS.
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The generation of an indole-2,3-quinodimethane intermediate and its use for the synthesis of indole alkaloids is described.
- Gallagher, Timothy,Magnus, Phillip
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p. 3889 - 3898
(2007/10/02)
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