- Total syntheses of indolactam alkaloids (-)-indolactam V, (-)-pendolmycin, (-)-lyngbyatoxin A, and (-)-teleocidin A-2
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We report the total syntheses of (-)-indolactam V and the C7-substituted indolactam alkaloids (-)-pendolmycin, (-)-lyngbyatoxin A, and (-)-teleocidin A-2. The strategy for preparing indolactam V relies on a distortion-controlled indolyne functionalization reaction to establish the C4-N linkage, in addition to an intramolecular conjugate addition to build the conformationally-flexible nine-membered ring. The total synthesis of indolactam V then sets the stage for the divergent synthesis of the other targeted alkaloids. Specifically, late-stage sp2-sp3 cross-couplings on an indolactam V derivative are used to introduce the key C7 substituents and the necessary quaternary carbons. These challenging couplings, in addition to other delicate manipulations, all proceed in the presence of a basic tertiary amine, an unprotected secondary amide, and an unprotected indole. Thus, our approach not only enables the enantiospecific total syntheses of four indolactam alkaloids, but also serves as a platform for probing complexity-generating and chemoselective transformations in the context of alkaloid total synthesis. This journal is the Partner Organisations 2014.
- Fine Nathel, Noah F.,Shah, Tejas K.,Bronner, Sarah M.,Garg, Neil K.
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p. 2184 - 2190
(2014/05/20)
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- Enzymatic production of (-)-indolactam V by LtxB, a cytochrome P450 monooxygenase
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The P450 cytochrome monooxygenase gene, ltxB, was cloned and overexpressed in Escherichia coli as a 6xHis-tagged protein. The resulting recombinant LtxB was purified by Ni-NTA affinity chromatography and characterized biochemically. Purified LtxB demonstrated typical cytochrome P450 spectroscopic properties including substrate-induced transition from a low-spin (λmax = 414 nm) to high-spin state (λmax = 386 nm) upon incubation with N-methyl-L-valyl-L-tryptophanol. The catalytic activity of LtxB was verified by demonstrating the oxidation/cyclization of N-methyl-L-valyl-L- tryptophanol to (-)-indolactam V. LtxB shows a relaxed specificity for analogue substrates in which the valyl group is substituted for other aliphatic groups. The relaxed substrate specificity of LtxB, along with the relaxed specificity of the prenyltransferase, LtxC, allowed for the enzymatic production of a series of (-)-indolactam V and lyngbyatoxin analogues.
- Huynh, Minh U.,Elston, Matthew C.,Hernandez, Nick M.,Ball, David B.,Kajiyama, Shin-Ichiro,Irie, Kazuhiro,Gerwick, William H.,Edwards, Daniel J.
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experimental part
p. 71 - 74
(2010/04/28)
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- Synthesis of Teleocidins A, B and Their Congeners. Part 2. Synthesis of Lyngbyatoxin A (Teleocidin A-1), Teleocidin A-2, Pendolmycin, and (R,E)- and (S,E)-7-(3,7,11-Trimethyl-1,6,10-dodecatrien-3-yl)-(-)-indolactams V
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Details of the synthesis method of the tumor promoters, lyngbyatoxin A (= teleocidin A-1) (1) and teleocidin A-2 (2) from (R)- and (S)-methyl N--N-methyl-L-valinate (3 and 4) are presented.Other titled compounds, 6, 7a, and 7b, were prepared analogously. Key words: alkaloid synthesis; lyngbyatoxin A, teleocidin A-2; pendolmycin; teleocidin analogs.
- Muratake, Hideaki,Okabe, Kazuaki,Natsume, Mitsutaka
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p. 8545 - 8558
(2007/10/02)
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- TOTAL SYNTHESIS OF LYNGBYATOXIN A (TELEOCIDIN A-1) AND TELEOCIDIN A-2
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An eleven step synthesis of tumor promoters, lyngbyatoxin A (=teleocidin A-1) (1) and teleocidin A-2 (2) was achieved from 1-tosylpyrrole (4) using a novel reaction forming 7-alkyl-4-aminoindoles (11).
- Muratake, Hideaki,Natsume, Mitsutaka
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p. 2265 - 2268
(2007/10/02)
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