- The enantiospecific, stereospecific total synthesis of the ring-A oxygenated sarpagine indole alkaloids (+)-majvinine, (+)-10-methoxyaffinisine, and (+)-Na-methylsarpagine, as well as the total synthesis of the Alstonia bisindole alkaloid macralstonidine
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The first stereospecific, enantiospecific total synthesis of the ring-A oxygenated sarpagine indole alkaloids (+)-Na-methylsarpagine (8), (+)-majvinine (14), and (+)-10-methoxyaffinisine (49), as well as the first total synthesis of the Alstonia bisindole alkaloid macralstonidine (9), has been accomplished. This approach employed the Schoellkopf chiral auxiliary for the stereospecific construction of the desired D-(+)-tryptophan unit required for the asymmetric Pictet-Spengler reaction. In addition, the strategy was doubly convergent for the enolate-mediated Pd0 coupling process and the asymmetric Pictet-Spengler reaction can be employed to synthesize both macroline (2) and Na-methylsarpagine (8), the coupling of which provides macralstonidine (9). This approach to ring-A substituted alkoxyindole alkaloids should find wide application for the synthesis of other alkaloids for it is stereospecific and either enantiomer can be prepared with ease.
- Zhao, Shuo,Liao, Xuebin,Wang, Tao,Flippen-Anderson, Judith,Cook, James M.
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p. 6279 - 6295
(2007/10/03)
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- Enantiospecific, stereospecific total synthesis of (+)-majvinine, (+)-10-methoxyaffinisine, and (+)-N(a)-methylsarpagine as well as the total synthesis of the Alstonia bisindole macralstonidine.
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[structure: see text] The enantiospecific stereospecific total synthesis of majvinine 1a, 10-methoxyaffinisine 1b, and N(a)-methylsarpagine 1c are reported; this method has also resulted in the total synthesis of the Alstonia bisindole macralstonidine 2.
- Zhao, Shuo,Liao, Xuebin,Cook, James M
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p. 687 - 690
(2007/10/03)
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