- Total syntheses of colchicine in comparison: A journey through 50 years of synthetic organic chemistry
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Colchicine, the major alkaloid of the meadow saffron, is one of the most prominent natural products and, like other tubulin-binding natural products (e.g. taxol and the epothilones), exhibits great pharmaceutical potential. The first syntheses in the late
- Graening, Timm,Schmalz, Hans-Guenther
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- Synthesis of Difluoromethyl Ketones from Weinreb Amides, and Tandem Addition/Cyclization of o-Alkynylaryl Weinreb Amides
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[Difluoro(phenylsulfanyl)methyl]trimethylsilane (PhSCF2SiMe3) underwent a fluoride-induced nucleophilic addition to the carbonyl group of Weinreb amides to provide the corresponding difluoro(phenylsulfanyl)methyl ketones. These were
- Phetcharawetch, Jongkonporn,Betterley, Nolan M.,Soorukram, Darunee,Pohmakotr, Manat,Reutrakul, Vichai,Kuhakarn, Chutima
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supporting information
p. 6840 - 6850
(2017/12/26)
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- Highly trans-Selective Arylation of Achmatowicz Rearrangement Products by Reductive γ-Deoxygenation and Heck-Matsuda Reaction: Asymmetric Total Synthesis of (-)-Musellarins A-C and Their Analogues
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Fully functionalized pyranuloses derived from Achmatowicz rearrangement (AR) are versatile building blocks in organic synthesis. However, access to trans-2,6-dihydropyrans from pyranuloses remains underexplored. Herein, we report a new two-step trans arylation of AR products to access 2,6-trans-dihydropyranones. This new trans-arylation method built on numerous plausible, but unsuccessful, direct arylation reactions, including Ferrier-type and Tsuji-Trost-type reactions, was finally enabled by an unprecedented, highly regioselective γ-deoxygenation of AR products by using Zn/HOAc and a diastereoselective Heck-Matsuda coupling. The synthetic utility of the reaction was demonstrated in the first asymmetric total synthesis of (-)-musellarins A-C and 12 analogues in 11-12 steps. The brevity and efficiency of our synthetic route permitted preparation of enantiomerically pure musellarins and analogues (>20 mg) for preliminary cytotoxicity evaluation, which led us to identify two analogues with three-to-six times greater potency than the musellarins as promising new leads. O leaves, Ar comes: A highly regio- and diastereoselective trans-arylation of Achmatowicz rearrangement products by an unprecedented Zn-mediated reductive γ-deoxygenation and Heck-Matsuda reaction was developed for the efficient synthesis of trans-2-aryl-6-alkyl dihydropyranones (see scheme: L.A.=Lewis acid). The synthetic utility of this new method was further demonstrated in the first asymmetric total synthesis of (-)-musellarins A-C and 12 analogues in 11-12 steps.
- Li, Zhilong,Ip, Fanny C. F.,Ip, Nancy Y.,Tong, Rongbiao
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p. 11152 - 11157
(2015/11/10)
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- Synthesis of indole-derived allocolchicine congeners through Pd-catalyzed intramolecular C-H arylation reaction
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The synthesis of several new heterocyclic structural analogs of the natural antimitotic agent allocolchicine is reported. As a key step an intramolecular Pd-catalyzed C-H arylation reaction was used to close the seven-membered ring fused with two electron
- Sitnikov, Nikolay S.,Kokisheva, Antonina S.,Fukin, Georgy K.,Neud?rfl, J?rg-Martin,Sutorius, Hannah,Prokop, Aram,Fokin, Valery V.,Schmalz, Hans-Günther,Fedorov, Alexey Yu.
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p. 6481 - 6492
(2016/02/18)
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- Facile construction of the colchicine skeleton by a rhodium-catalyzed cyclization/cycloaddition cascade
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The major alkaloid of the meadow saffron is colchicine, which displays remarkable antimitotic activity and has long been used in the treatment of acute gout and is currently being tested against a broad variety of other diseases. In a remarkable Rh-cataly
- Graening, Timm,Friedrichsen, Willy,Lex, Johann,Schmalz, Hans-Guenther
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p. 1524 - 1526
(2007/10/03)
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- A mild, one-pot method for the conversion of carboxylic acids into the corresponding Weinreb amides
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Reaction of various carboxylic acids with N,O-dimethylhydroxylamine under modified Mukaiyama amide coupling conditions affords the corresponding Weinerb amides in generally high yield.
- Banwell,Smith
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p. 2011 - 2019
(2007/10/03)
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