- A diastereoselective oxa-pictet-spengler-based strategy for (+)-frenolicin B and epi -(+)-frenolicin B synthesis
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An efficient diastereoselective oxa-Pictet-Spengler reaction strategy was developed to construct benzoisochroman diastereomers. The utility of the reaction was demonstrated in the context of both the total synthesis of naturally occurring pyranonaphthoquinones (+)-frenolicin B and epi-(+)-frenolicin B as well as a range of frenolicin precursor analogs. The method is versatile and offers exquisite stereocontrol and, as such, offers a synthetic advance for the synthesis of pyranonaphthoquinone analogs.
- Zhang, Yinan,Wang, Xiachang,Sunkara, Manjula,Ye, Qing,Ponomereva, Larissa V.,She, Qing-Bai,Morris, Andrew J.,Thorson, Jon S.
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- The divergent asymmetric synthesis of kalafungin, 5-epi-frenolicin B and related pyranonaphthoquinone antibiotics
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A divergent, asymmetric method for the synthesis of pyranonaphthoquinones is reported. The synthetic strategy applies a Staunton-Weinreb annulation between substituted ortho-toluates and the (R)-pyran-2-one 7 to construct the key naphthopyranone intermediates. Stereoselective introduction of either a methyl or propyl C5 alkyl substituent by use of Grignard addition/silane- mediated reduction and a sequence of oxidations gave a series of pyranonaphthoquinones including kalafungin 1, 5-epi-9-methoxykalafungin 34 and 5-epi-frenolicin B 24.
- Donner, Christopher D.
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p. 377 - 386
(2013/01/15)
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- A chiron approach to the total synthesis of (-)-juglomycin A, (+)-kalafungin, (+)-frenolicin B, and (+)-deoxyfrenolicin
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A general, efficient, and common strategy for the synthesis of (-)-juglomycin A, (+)-kalafungin, (+)-frenolicin B, and (+)-deoxyfrenolicin is reported here. The strategy involves the synthesis of a key building block alkyne from a cheap chiral pool material, d-glucono-δ-lactone, Doetz benzannulation, oxa-Pictet-Spengler reaction, and H2SO 4-mediated epimerization.
- Fernandes, Rodney A.,Chavan, Vijay P.,Mulay, Sandip V.,Manchoju, Amarender
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p. 10455 - 10460
(2013/01/15)
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- 3. Naphthopyranquinone Antibiotics: Novel Enantioselective Syntheses of Frenolicin B and Some of Its Stereoisomers
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Two new enantioselective syntheses of the naphthopyranquinone antibiotic frenolicin B (1), of its enantiomer 2, and of its diastereoisomers 3 and 4 were accomplished using two different routes from optically active β-hydroxy esters (R)- and (S)-11 and 18.
- Masquelin, Thierry,Hengartner, Urs,Streith, Jacques
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- Direct Total Syntheses of Frenolicin B and Kalafungin via Highly Regioselective Diels-Alder Reactions
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Frenolicin B, an anticoccidial agent, has been synthesizes in six steps from ketone 3.Racemic kalafungin, an antifungal agent, has been synthesized in five steps.The key step in both syntheses, a regioselective Diels-Alder reaction, proceeds with complete
- Kraus, George A.,Li, Jun,Gordon, Mark S.,Jensen, Jan H.
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p. 1154 - 1159
(2007/10/02)
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- TOTAL SYNTHESIS OF (+-)-NANAOMYCIN A AND (+-)-FRENOLICIN
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Efficient synthesis of (+-)-nanaomycin A and (+-)-frenolicin from a versatile intermediate is described.
- Ichihara, Akitami,Ubukata, Makoto,Oikawa, Hideaki,Murakami, Kazuo,Sakamura, Sadao
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p. 4469 - 4472
(2007/10/02)
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