- A novel and general synthetic pathway to strychnos indole alkaloids: Total syntheses of (-)-tubifoline, (-)-dehydrotubifoline, and (-)-strychnine using palladium-catalyzed asymmetric allylic substitution
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A method of palladium-catalyzed asymmetric allylic substitution for synthesizing 2-substituted cyclohexenylamine derivatives was established. Treatment of a 2-silyloxymethylcyclohexenol derivative with ortho-bromo-N-tosylaniline in the presence of Pd2dba 3·CHCl3 and (S)-BINAPO in THF afforded a cyclohexenylamine derivative with 84% ee in 80% yield. The Heck reaction was carried out to produce an indolenine derivative in good yield. Using this method, we synthesized indolenine derivative 7, which was recrystallized from EtOH to give an optically pure compound. From this compound, tetracyclic ketone 13, which should be a useful intermediate for the synthesis of indole alkaloids, could be synthesized. The total syntheses of (-)-dehydrotubifoline, (-)-tubifoline, and (-)-strychnine were achieved from 13. All ring constructions for the syntheses of these natural products were achieved using a palladium catalyst.
- Mori, Miwako,Nakanishi, Masato,Kajishima, Daisuke,Sato, Yoshihiro
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p. 9801 - 9807
(2007/10/03)
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- A new and general synthetic pathway to strychnos indole alkaloids: total syntheses of (-)-dehydrotubifoline and (-)-tubifoline by palladium-catalyzed asymmetric allylic substitution.
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[see reaction]. A novel procedure for the synthesis of an indole skeleton was developed. Treatment of a cyclohexenol derivative having a silyloxymethyl group at the 2-position with N-tosyl-o-bromoaniline in the presence of Pd2dba3*CHCl3 and (S)-BINAPO gav
- Mori,Nakanishi,Kajishima,Sato
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p. 1913 - 1916
(2007/10/03)
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