- Biomimetic Total Syntheses of Clavine Alkaloids
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Biomimetic total syntheses of either enantiomers of a number of ergot alkaloids, chanoclavine I (1b), chanoclavine I aldehyde (1c), pyroclavine (1e), festuclavine (1f), pibocin A (1g), 9-deacetoxyfumigaclavine C (1h), and fumigaclavine G (1i), have been achieved from seco-agroclavine (1a). The advanced intermediate for seco-agroclavine (1a) was synthesized via a key thiourea-catalyzed intramolecular nitronate addition onto α,β-unsaturated ester.
- Chaudhuri, Saikat,Bhunia, Subhajit,Roy, Avishek,Das, Mrinal K.,Bisai, Alakesh
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p. 288 - 291
(2018/01/17)
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- Total Synthesis of (-)-Chanoclavine i and an Oxygen-Substituted Ergoline Derivative
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An efficient and direct route to ergot alkaloid (-)-chanoclavine I (3) is described using the inexpensive compound (2R)-(+)-phenyloxirane (15) as a chiral pool in 13 steps with 17% overall yield. Key features of the synthesis include a palladium-catalyzed intramolecular aminoalkynylation of terminal olefin and a rhodium-catalyzed intramolecular [3 + 2] annulation. An oxygen-substituted ergoline derivative (-)-25 was also achieved by using the same strategy.
- Lu, Jia-Tian,Shi, Zi-Fa,Cao, Xiao-Ping
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supporting information
p. 7774 - 7782
(2017/08/14)
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- Synthetic studies directed toward ergot alkaloids, (±)-6,7-secoagroclavine, (±)-chanoclavine-1, (±)-chanoclavine-II, and (±)-agroclavine-I, by an efficient and common synthetic route
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Novel three synthetic routes to (±)-6,7-secoagroclavine were developed from either methyl 3-(3-formylindol-4-yl)acrylate, indole-4-carbaldehyde, or 4-iodoindole-3-carbaldehyde. The total syntheses of (±)-chanoclavine-I, (±)-chanoclavine-II, and (±)-agroclavine-I were accomplished as well from the synthetic intermediates involved in the synthesis of (±)-6,7-secoagroclavine, culminating in establishing an efficient and common synthetic method for ergot alkaloids.
- Yamada, Fumio,Makita, Yoshihiko,Somei, Masanori
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p. 599 - 620
(2008/03/12)
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- Simple total syntheses of (-)-ergot alkaloids and their (+)-enantiomers by a common synthesis method utilizing optical resolution
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The first and simple total syntheses of (-)-isochanoclavine-1 ((-)-1b), (-)-agroclavine ((-)-3), (-)-agroclavine-1 ((-)-4), and (-)-norchanoclavine-1 ((-)-5c) and their (+)-enantiomers are achieved from indole-3-carboxaldehyde (8) by a common synthesis method utilizing optical resolution. Absolute configuration of (-)-agroclavine-1 is determined to be 5R and 10S for the first time. Preparations of both enantiomers of chanoclavine-1 (1c) are also included.
- Somei, Masanori,Nakagawa, Kyoko
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p. 1263 - 1266
(2007/10/03)
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- Total synthesis of optically active chanoclavine-I
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The total synthesis of optically active chanoclavine-I, an ergot alkaloid, was accomplished using palladium-catalyzed intramolecular cyclization (Heck-reaction) as a key step. The conjugate ester (6) was obtained in 2 steps from optically active 4-bromotryptophan (10), and the cyclization of 6 proceeded smoothly without racemization to give the key intermediate, tricyclic tetrahydrobenz[c,d]indole derivative (7), in high yield.
- Yokoyama, Yuusaku,Kondo, Kazuhiro,Mitsuhashi, Masako,Murakami, Yasuoki
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p. 9309 - 9312
(2007/10/03)
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- Photocyclisation of Enamides. Part 35. New Total Syntheses of the Ergot Alkaloids (+/-)-Chanoclavine-I and (+/-)-isochanoclavine-I using a Fragmentation of 3-Amino Alcohols
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A new synthetic route involving the fragmentation reaction of 3-amino alcohols for the total synthesis of 6,7-secoergoline alkaloids was developed and then successfully applied to the total syntheses of (+/-)-chanoclavine-I and (+/-)-isochanoclavine-I.
- Ninomiya, Ichiya,Habe, Naoko,Kiguchi, Toshiko,Naito, Takeaki
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p. 3275 - 3285
(2007/10/02)
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- THE FIRST TOTAL SYNTHESIS OF (+/-)-CHANOCLAVINE-I ACID AND AN ALTERNATIVE TOTAL SYNTHESIS OF (+/-)-CHANOCLAVINE-I
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The total synthesis of (+/-)-chanoclavine-I acid was achieved for the first time.An alternative total synthesis of (+/-)-chanoclavine-I was also reported.
- Somei, Masanori,Mukaiyama, Harunobu,Nomura, Yoko,Nakagawa, Kyoko
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p. 1919 - 1921
(2007/10/02)
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- A NOVEL SYNTHESIS OF (+/-)-ISOCHANOCLAVINE-I
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Total synthesis of (+/-)-isochanoclavine-I (9) was achieved via the route involving fragmentation reaction of the 3-aminoalcohol 4.
- Kiguchi, Toshiko,Kuninobu, Naoko,Naito, Takeaki,Ninomiya, Ichiya
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- TOTAL SYNTHESES OF (+/-)-AGROCLAVINE-I, (+/-)-6-NOR-CHANOCLAVINE-II, AND (+/-)-CHANOCLAVINE-II
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The first total syntheses of (+/-)-6-nor-chanoclavine-II and (+/-)-chanoclavine-II are achieved.Total synthesis of (+/-)-agroclavine-I is also reported.
- Somei, Masanori,Yamada, Fumio,Makita, Yoshihiko
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p. 895 - 898
(2007/10/02)
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- SHORT-STEP SYNTHESIS OF THE ERGOT ALKALOIDS, (+/-)-NORCHANOCLAVINE-I, (+/-)-CHANOCLAVINE-I, (+/-)-ISOCHANOCLAVINE-I, and (+/-)-AGROCLAVINE
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The simple total synthesis of the ergot alkaloids, (+/-)-norchanoclavine-I, (+/-)-chanoclavine-I, (+/-)-isochanoclavine-I, and (+/-)-agroclavine was achieved by a practical and common synthesis method.A new regio-selective oxidation of the Z-methyl group of the isoprenyl system with selenium dioxide is described.Keywords - (+/-)-norchanoclavine-I; (+/-)-norisochanoclavine-I; (+/-)-chanoclavine-I; (+/-)-isochanoclavine-I; (+/-)-agroclavine; ergot alkaloid; total synthesis; common synthesis method; new oxidation
- Somei, Masanori,Makita, Yoshihiko,Yamada, Fumio
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p. 948 - 950
(2007/10/02)
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- TOTAL SYNTHESES OF CLAVINE ALKALOIDS BY AN INTRAMOLECULAR NITRONE-OLEFIN CYCLOADDITION REACTION
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The racemic ergot alkaloids chanoclavine I (1) and 6,7-secoagroclavine (4) have been synthesized stereoselectively from indole-4-carboxaldehyde (7) in overall yields of 14 and 13 percent, respectively.Further syntheses of isochanoclavine I (2), paliclavine (5) and costaclavine (6), via the same isoxazolidine 18 are described.The key step 16-->18 (Scheme 4) involves a transient nitrone 17 which undergoes a kinetically controlled, regio- and stereoselective intramolecular cycloaddition to a 1,2-disubstituted olefinic bond.
- Oppolzer, W.,Grayson, J. I.,Wegmann, H.,Urrea, M.
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p. 3695 - 3706
(2007/10/02)
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- TOTAL SYNTHESES OF (+/-)-CHANOCLAVINE I AND (+/-)-DIHYDROSETOCLAVINE
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Syntheses of the title ergot alkaloids 5 and 19a were achieved from the common intermediate 2, obtained by a series of reactions including our synthetic method of 4-alkylindoles.
- Natsume, Mitsutaka,Muratake, Hideaki
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p. 375 - 379
(2007/10/02)
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- 178. Stereoselective Total Syntheses of (+/-)-Chanoclavine I and (+/-)-Isochanoclavine I by an Intramolecular Nitrone-Olefin/Cycloaddition
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The racemic alkaloids chanoclavine I (1) and isochanoclavine I (2) have been synthesized stereoselectively from indole-4-carbaldehyde (3) by a sequence of 11 operations in overall yields of 14percent and 2.4percent, respectively.The key step 6->8 (Scheme 2) involves a transient nitrone 7 which undergoes a regio- and stereoselective intramolecular cycloaddition to a 1,2-disubstituted olefinic bond.
- Oppolzer, Wolfgang,Grayson, J. Ian
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p. 1706 - 1710
(2007/10/02)
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- PREPARATION AND USE OF NITROGEN- OR SULFUR CONTAINING HETEROCYCLES IN ORGANIC SYNTHESIS
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The utility of intramolecular cycloadditions of ortho-quinodimethanes for the synthesis of complex polycyclic molecules is illustrated: 1) by the stereoselective synthesis of the natural alkaloid (+/-)-chelidonine starting from a benzocyclobutene; 2) by t
- Oppolzer, Wolfgang
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p. 1615 - 1630
(2007/10/02)
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