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Xu Z, DiBello M, Wang Z, Rose JA, Chen L, Li X, Herzon SB. Stereocontrolled Synthesis of the Fully Glycosylated Monomeric Unit of Lomaiviticin A. J Am Chem Soc 2022; 144:16199-16205. [PMID: 35998350 DOI: 10.1021/jacs.2c07631] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We describe a stereocontrolled synthesis of 3, the fully glycosylated monomeric unit of the dimeric cytotoxic bacterial metabolite (-)-lomaiviticin A (2). A novel strategy involving convergent, site- and stereoselective coupling of the β,γ-unsaturated ketone 6 and the naphthyl bromide 7 (92%, 15:1 diastereomeric ratio (dr)), followed by radical-based annulation and silyl ether cleavage, provided the tetracycle 5 (57% overall), which contains the carbon skeleton of the aglycon of 3. The β-linked 2,4,6-trideoxy-4-aminoglycoside l-pyrrolosamine was installed in 73% yield and with 15:1 β:α selectivity using a modified Koenigs-Knorr glycosylation. The diazo substituent was introduced via direct diazo transfer to an electron-rich benzoindene (4 → 27). The α-linked 2,6-dideoxyglycoside l-oleandrose was introduced by gold-catalyzed activation of an o-alkynyl glycosylbenzoate (75%, >20:1 α:β selectivity). A carefully orchestrated endgame sequence then provided efficient access to 3. Cell viability studies indicated that monomer 3 is not cytotoxic at concentrations up to 1 μM, providing conclusive evidence that the dimeric structure of (-)-lomaiviticin A (2) is required for cytotoxic effects. The preparation of 3 provides a foundation to complete the synthesis of (-)-lomaiviticin A (2) itself.
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Affiliation(s)
- Zhi Xu
- Department of Chemistry, Yale University, New Haven, Connecticut06520, United States
| | - Mikaela DiBello
- Department of Chemistry, Yale University, New Haven, Connecticut06520, United States
| | - Zechun Wang
- Department of Chemistry, Yale University, New Haven, Connecticut06520, United States
| | - John A Rose
- Department of Chemistry, Yale University, New Haven, Connecticut06520, United States
| | - Lei Chen
- Department of Chemistry, Yale University, New Haven, Connecticut06520, United States
| | - Xin Li
- Department of Chemistry, Yale University, New Haven, Connecticut06520, United States
| | - Seth B Herzon
- Department of Chemistry, Yale University, New Haven, Connecticut06520, United States.,Departments of Pharmacology and Therapeutic Radiology, Yale School of Medicine, New Haven, Connecticut06520, United States
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Rose JA, Mahapatra S, Li X, Wang C, Chen L, Swick SM, Herzon SB. Synthesis of the bis(cyclohexenone) core of (-)-lomaiviticin A. Chem Sci 2020; 11:7462-7467. [PMID: 34123029 PMCID: PMC8159427 DOI: 10.1039/d0sc02770g] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
(-)-Lomaiviticin A is a complex C 2-symmetric bacterial metabolite comprising two diazotetrahydrobenzo[b]fluorene (diazofluorene) residues and four 2,6-dideoxy glycosides, α-l-oleandrose and N,N-dimethyl-β-l-pyrrolosamine. The two halves of lomaiviticin A are linked by a single carbon-carbon bond oriented syn with respect to the oleandrose residues. While many advances toward the synthesis of lomaiviticin A have been reported, including synthesis of the aglycon, a route to the bis(cyclohexenone) core bearing any of the carbohydrate residues has not been disclosed. Here we describe a short route to a core structure of lomaiviticin A bearing two α-l-oleandrose residues. The synthetic route features a Stille coupling to form the conjoining carbon-carbon bond of the target and a double reductive transposition to establish the correct stereochemistry at this bond. Two synthetic routes were developed to elaborate the reductive transposition product to the bis(cyclohexenone) target. The more efficient pathway features an interrupted Barton vinyl iodide synthesis followed by oxidative elimination of iodide to efficiently establish the enone functionalities in the target. The bis(cyclohexenone) product may find use in a synthesis of lomaiviticin A itself.
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Affiliation(s)
- John A Rose
- Department of Chemistry, Yale University New Haven Connecticut 06520 USA
| | - Subham Mahapatra
- Department of Chemistry, Yale University New Haven Connecticut 06520 USA
| | - Xin Li
- Department of Chemistry, Yale University New Haven Connecticut 06520 USA
| | - Chao Wang
- Department of Chemistry, Yale University New Haven Connecticut 06520 USA
| | - Lei Chen
- Department of Chemistry, Yale University New Haven Connecticut 06520 USA
| | - Steven M Swick
- Department of Chemistry, Yale University New Haven Connecticut 06520 USA
| | - Seth B Herzon
- Department of Chemistry, Yale University New Haven Connecticut 06520 USA .,Department of Pharmacology, Yale School of Medicine New Haven Connecticut 06520 USA
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Herzon SB, Woo CM. The diazofluorene antitumor antibiotics: Structural elucidation, biosynthetic, synthetic, and chemical biological studies. Nat Prod Rep 2012; 29:87-118. [DOI: 10.1039/c1np00052g] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Gholap SL, Woo CM, Ravikumar PC, Herzon SB. Synthesis of the Fully Glycosylated Cyclohexenone Core of Lomaiviticin A. Org Lett 2009; 11:4322-5. [DOI: 10.1021/ol901710b] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | - Christina M. Woo
- Department of Chemistry, Yale University, New Haven, Connecticut 06520
| | - P. C. Ravikumar
- Department of Chemistry, Yale University, New Haven, Connecticut 06520
| | - Seth B. Herzon
- Department of Chemistry, Yale University, New Haven, Connecticut 06520
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Brasholz M, Reißig HU. Alkoxyallene-Based De Novo Synthesis of Rare Deoxy Sugars: New Routes to L-Cymarose, L-Sarmentose, L-Diginose and L-Oleandrose. European J Org Chem 2009. [DOI: 10.1002/ejoc.200900450] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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6
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Wittig approach to carbohydrate-derived vinyl sulfides, new substrates for regiocontrolled ring-closure reactions. Tetrahedron 2004. [DOI: 10.1016/j.tet.2003.12.040] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Vincent SP, Burkart MD, Tsai CY, Zhang Z, Wong CH. Electrophilic Fluorination−Nucleophilic Addition Reaction Mediated by Selectfluor: Mechanistic Studies and New Applications. J Org Chem 1999; 64:5264-5279. [DOI: 10.1021/jo990686h] [Citation(s) in RCA: 133] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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8
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Bredenkamp MW, Holzapfel CW, Toerien F. Alternative Syntheses of L-(-)-Oleandrose from L-Rhamnose1Preparation of Glycals. SYNTHETIC COMMUN 1992. [DOI: 10.1080/00397919208021642] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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9
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De novo highly stereocontrolled synthesis of 2,6-dideoxy sugars by use of 2,6-anhydro-2-thio sugars. Carbohydr Res 1991. [DOI: 10.1016/0008-6215(91)89016-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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