Synthetic Applications of 2-(1,3-Dithian-2-yl)indoles. 7. Synthesis of Aspidospermidine
- 1 January 1996
- journal article
- Published by American Chemical Society (ACS) in The Journal of Organic Chemistry
- Vol. 61 (22), 7882-7888
- https://doi.org/10.1021/jo9609900
Abstract
A new method of synthesizing the alkaloid aspidospermidine (1), based on building ring E on the pyridocarbazole [ABCD] ring structure, is reported. The preparation of the pyridocarbazole framework of Aspidosperma alkaloids is a new three-step synthetic application of 2-(1,3-dithian-2-yl)indoles. A tandem conjugate addition−alkylation reaction starting from indolyldithiane (4), 3-methylenelactam 6, and EtI yields the adduct 17. Treatment of lactam 17 with DIBALH leads to formation of the naphthyridoindole 18. Compound 18 isomerizes in aqueous AcOH to yield pyridocarbazole 3. Finally, closure of ring E and subsequent reduction of the dithiane ring produces aspidospermidine. Pyridocarbazoles 2 and 10 were prepared as models.Keywords
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