- Regioselective Direct C-4 Functionalization of Indole: Total Syntheses of (-)-Agroclavine and (-)-Elymoclavine
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An efficient rhodium-catalyzed method for direct C-H functionalization at the C4 position of unprotected indoles has been developed. The utility of this method is demonstrated by the concise total syntheses of agroclavine and elymoclavine in a divergent manner. These syntheses feature a Pd-catalyzed asymmetric allylic alkylation reaction to assemble the triyclic indole moiety, and a ring-closing metathesis reaction to form the D ring.
- Lv, Jianbo,Wang, Bin,Yuan, Kuo,Wang, Yuan,Jia, Yanxing
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p. 3664 - 3667
(2017/07/15)
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- Dehydrogenation with Benzeneseleninic Anhydride in the Total Synthesis of Ergot Alkaloids
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Investigation of the dehydrogenative conversion of indolines into indoles with benzeneseleninic anhydride (1) resulted in the development of an efficient standardised procedure, which was successfully applied to the final steps in first total synthesis of (+/-)-lysergol (18), (+/-)-isolysergol (27), and (+/-)-elymoclavine (29).
- Ninomiya, Ichiya,Hashimoto, Chiyomi,Kiguchi, Toshiko,Naito, Takeaki,Barton, Derek, H. R.,et al.
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p. 707 - 713
(2007/10/02)
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- Probing Ergot Alkaloid Biosynthesis: Synthesis and Feeding of a Proposed Intermediate along the Biosynthetic Pathway. A New Amidomalonate for Tryptophan Elaboration
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The total synthesis of the diastereoisomeric amino acids 2 and their N-trideuteriomethyl analogues has been carried out.These compounds represent possible intermediates along the biosynthetic pathway from 4-(γ,γ-dimethylallyl)tryptophan (1) to the ergot alkaloids (e.g., 3a).The synthetic scheme features the preparation of an (indolylvinyl)metalic reagent from 4-ethynylindole via a hydrostannylation/metal-metal exchange sequence, as well as the preparation of dimethyl amino>malonate, a new amidomalonate reagent for tryptophan elaboration.Incorporation experiments with Claviceps sp.SD58 followed by GC-MS analysis of the major alkaloid, elymoclavine, showed that neither diastereomer of 2-d3 is an ergot alkaloid precursor.
- Kozikowski, Alan P.,Okita, Makoto,Kobayashi, Motomasa,Floss, Heinz G.
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p. 863 - 869
(2007/10/02)
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- TOTAL SYNTHESIS OF ERGOT ALKALOIDS, (+/-)-ELYMOCLAVINE AND (+/-)-ISOLYSERGOL
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Two of the hitherto untouched ergot alkaloids, (+/-)-elymoclavine and (+/-)-isolysergol, were synthesized according to the synthetic route involving enamide photocyclization.
- Ninomiya, Ichiya,Hashimoto, Chiyomi,Kiguchi, Toshiko
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p. 1035 - 1038
(2007/10/02)
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