151
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Synthesis and Use of New Substituted 1,3,5-Hexatrienes in Studying Thermally Induced 6π-Electrocyclizations. European J Org Chem 2007. [DOI: 10.1002/ejoc.200700201] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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152
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Steven A, Overman L. Totalsynthese komplexer Cyclotryptaminalkaloide: stereokontrollierter Aufbau quartärer Kohlenstoffstereozentren. Angew Chem Int Ed Engl 2007. [DOI: 10.1002/ange.200700612] [Citation(s) in RCA: 125] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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153
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Regioselective hydrostannation of activated alkynes catalyzed by in situ generated copper hydride. Tetrahedron 2007. [DOI: 10.1016/j.tet.2007.04.085] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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154
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Lin H, Kazmaier U. Regioselective Mo-Catalyzed Hydrostannations as Key Steps in the Synthesis of Functionalized Amino Alcohols and Heterocycles. European J Org Chem 2007. [DOI: 10.1002/ejoc.200700126] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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155
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Studies directed towards the total synthesis of lycoperdinosides: stereoselective construction of the C1–C9 and C10–C21 segments of the molecules. Tetrahedron Lett 2007. [DOI: 10.1016/j.tetlet.2007.04.016] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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156
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Hamze A, Provot O, Brion JD, Alami M. Regiocontrol of the Palladium-Catalyzed Tin Hydride Addition to Z-Enynols: Remarkable Z-Directing Effects. J Org Chem 2007; 72:3868-74. [PMID: 17432910 DOI: 10.1021/jo0701435] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Palladium-catalyzed hydrostannation of substituted Z- and E-enynols is discussed and compared. The regioselectivity of the H-Sn bond addition was found to be controlled by the geometry of the double bond (Z- or syn-directing effect) rather than the nature of its substituents. Exclusively alpha-vinyl stannanes were obtained from Z-enynols having various substituents on the double bond regardless of their electronic, steric, or chelating natures.
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Affiliation(s)
- Abdallah Hamze
- Univ Paris-Sud, and CNRS, BioCIS UMR 8076, Laboratoire de Chimie Thérapeutique, Faculté de Pharmacie, 5 rue J.-B. Clément, Châtenay-Malabry, F-92296, France
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157
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Padwa A, Zhang H. Synthesis of some members of the hydroxylated phenanthridone subclass of the Amaryllidaceae alkaloid family. J Org Chem 2007; 72:2570-82. [PMID: 17338575 PMCID: PMC2475589 DOI: 10.1021/jo0626111] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The total synthesis of several members of the hydroxylated phenanthridone subclass of the Amaryllidaceae alkaloid family has been carried out. (+/-)-Lycoricidine and (+/-)-7-deoxypancratistatin were assembled through a one-pot Stille/intramolecular Diels-Alder cycloaddition cascade to construct the core skeleton. The initially formed [4+2]-cycloadduct undergoes nitrogen-assisted ring opening followed by a deprotonation/reprotonation of the resulting zwitterion to give a rearranged hexahydroindolinone on further heating at 160 degrees C. The stereochemical outcome of the IMDAF cycloaddition has the side arm of the tethered vinyl group oriented exo with respect to the oxygen bridge. The resulting cycloadduct was used for the stereocontrolled installation of the remaining functionality present in the C-ring of the target molecules. Key features of the synthetic strategy include (1) a lithium hydroxide induced tandem hydrolysis/decarboxylation/elimination sequence to introduce the required pi-bond in the C-ring of (+/-)-lycoricidine, and (2) conversion of the initially formed Diels-Alder adduct into an aldehyde intermediate which then undergoes a stereospecific decarbonylation reaction mediated by Wilkinson's catalyst to set the trans-B-C ring junction of (+/-)-7-deoxypancratistatin.
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Affiliation(s)
- Albert Padwa
- Department of Chemistry, Emory University, Atlanta, Georgia 30322, USA.
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158
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Toscano MD, Payne RJ, Chiba A, Kerbarh O, Abell C. Nanomolar Inhibition of Type II Dehydroquinase Based on the Enolate Reaction Mechanism. ChemMedChem 2007; 2:101-12. [PMID: 17068841 DOI: 10.1002/cmdc.200600194] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
We describe the rational design of a novel, highly potent inhibitor of type II dehydroquinase, the dicarboxylate 6. The incorporation of a carboxylate at the 3-position mimics the putative enolate intermediate in the reaction mechanism, and allows a potential electrostatic binding interaction with the arginine on the active site flap. This results in a 1000-fold increase in potency, making the dicarboxylate 6 the most potent inhibitor of type II dehydroquinase reported to date, with a high ligand efficiency of -0.68 kcal mol(-1) per nonhydrogen atom. The systematic dissection of 6 in compounds 7-12, all of which show a drop in potency, confirm the synergistic importance of the two carboxylates, the C3 and C4 hydroxyl groups, and the anhydroquinate ring structure for the potency of 6.
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Affiliation(s)
- Miguel D Toscano
- Department of Chemistry, University of Cambridge, University Chemical Laboratory, Lensfield Road, Cambridge, CB2 1EW, UK
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159
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Yamano Y, Ito M. Total synthesis of capsanthin and capsorubin using Lewis acid-promoted regio- and stereoselective rearrangement of tetrasubsutituted epoxides. Org Biomol Chem 2007; 5:3207-12. [PMID: 17878980 DOI: 10.1039/b710386g] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The synthesis of capsanthin 1 and capsorubin 2 was accomplished via the C(15)-cyclopentyl ketone 6 prepared by Lewis acid-promoted regio- and stereoselective rearrangement of the epoxy dienal 5.
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Affiliation(s)
- Yumiko Yamano
- Kobe Pharmaceutical University, Motoyamakita-Machi, Kobe, Japan.
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160
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Abstract
The synthesis of several γ,δ-unsaturated-α-amino acid derivatives is described. The method features regioselective stannylation of propargylglycine derivatives followed by Stille coupling reactions.
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Affiliation(s)
- Siyuan Chen
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523; University of Colorado Cancer Center, Aurora, CO 80045
| | - Robert M. Williams
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523; University of Colorado Cancer Center, Aurora, CO 80045
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161
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Moreno-Mañas M, Pleixats R, Roglans A. Diels-Alder Reactions of 1,1-Disubstituted 3,4-Dimethylene-cyclopentanes. Preparation of Indanes and Diazaindanes. SYNTHETIC COMMUN 2006. [DOI: 10.1080/00397919308009818] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Marcial Moreno-Mañas
- a Department of Chemistry , Universitat Autónoma de Barcelona , Bellaterra, 08193, Barcelona, Spain
| | - Roser Pleixats
- a Department of Chemistry , Universitat Autónoma de Barcelona , Bellaterra, 08193, Barcelona, Spain
| | - Anna Roglans
- a Department of Chemistry , Universitat Autónoma de Barcelona , Bellaterra, 08193, Barcelona, Spain
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162
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Total synthesis of the epoxyquinol dimer (+)-panepophenanthrin: application of a diastereospecific biomimetic Diels–Alder dimerisation. Tetrahedron 2006. [DOI: 10.1016/j.tet.2006.08.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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163
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Schuppan J, Wehlan H, Keiper S, Koert U. Apoptolidinone A: Synthesis of the Apoptolidin A Aglycone. Chemistry 2006; 12:7364-77. [PMID: 16865756 DOI: 10.1002/chem.200600461] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
An efficient stereocontrolled synthesis of apoptolidinone A, the aglycone of apoptolidin A is described. The synthetic strategy relies on a cross coupling between C11/C12 of a northern half (C1-C11) and a southern part (C12-C28) followed by a ring-size selective macrolactonization. Key steps for the introduction of the southern half stereocenters are a stereoselective aldol reaction, a substrate controlled dihydroxylation and a chelation-controlled Grignard/aldehyde addition. The conjugated triene of the northern half was built up successively by E-selective Wittig reactions. L-Malic acid was chosen as the chiral pool source for the C8/C9 stereocenters. The final cleavage of the silyl ethers and the conversion of the C21 methyl ketal into the hemiketal was achieved by HF.pyridine.
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Affiliation(s)
- Julia Schuppan
- Fachbereich Chemie, Philipps-Universität Marburg, Hans-Meerwein-Strasse, 35032 Marburg, Germany
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164
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Porco JA, Su S, Lei X, Bardhan S, Rychnovsky SD. Total Synthesis and Structure Assignment of (+)-Hexacyclinol. Angew Chem Int Ed Engl 2006; 45:5790-2. [PMID: 16871643 DOI: 10.1002/anie.200602854] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- John A Porco
- Department of Chemistry, Boston University, Boston, MA 02215, USA
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165
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166
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Amans D, Bellosta V, Cossy J. Total Synthesis of Pseudotrienic Acid B: A Bioactive Metabolite fromPseudomonas sp. MF 381-IODS. Angew Chem Int Ed Engl 2006. [DOI: 10.1002/ange.200601114] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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167
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Amans D, Bellosta V, Cossy J. Total Synthesis of Pseudotrienic Acid B: A Bioactive Metabolite fromPseudomonas sp. MF 381-IODS. Angew Chem Int Ed Engl 2006; 45:5870-4. [PMID: 16881023 DOI: 10.1002/anie.200601114] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Dominique Amans
- Laboratoire de Chimie Organique associé au CNRS, ESPCI, 10 rue Vauquelin, 75231 Paris Cedex 05, France
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168
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Ma Y, Huang X. A Regiospecific Synthesis of 1-Iodo Arylselenoethenes via Hydrostannation of Arylselenoethynes. SYNTHETIC COMMUN 2006. [DOI: 10.1080/00397919708005021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Yun Ma
- a Department of Chemistry , Hangzhou University , Hangzhou, 310028, P. R. China
| | - Xian Huang
- a Department of Chemistry , Hangzhou University , Hangzhou, 310028, P. R. China
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169
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Yang DY, He J, Miao S. A Regio- and Stereoselective Route to (E)-Stannylenynes by Cross-Coupling of Stannyl Vinyldialkylboranes with Alkynyl(phenyl)iodonium Tosylates. SYNTHETIC COMMUN 2006. [DOI: 10.1081/scc-120021991] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- De-Yu Yang
- a Department of Chemistry , Zhejiang University (Xi-xi Campus) , Hangzhou, P.R. China
| | - Jun He
- a Department of Chemistry , Zhejiang University (Xi-xi Campus) , Hangzhou, P.R. China
| | - Sheng Miao
- a Department of Chemistry , Zhejiang University (Xi-xi Campus) , Hangzhou, P.R. China
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170
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Béji F, Lebreton J, Villiéras J, Amri H. STEREOSELECTIVE AND STEREOSPECIFIC SYNTHESIS OF 2-ALKYLIDENE-3-METHYLENE SUCCINIC ACID DIMETHYL ESTERS. SYNTHETIC COMMUN 2006. [DOI: 10.1081/scc-120014031] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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171
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Zhong P, Xiong ZX, Huang X. A STEREOSELECTIVE SYNTHETIC ROUTE TO (Z)-α-STANNYL-α,β-UNSATURATED ESTERS. SYNTHETIC COMMUN 2006. [DOI: 10.1081/scc-100000215] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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172
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Bourdron J, Commeiras L, Barbier P, Bourgarel-Rey V, Pasquier E, Vanthuyne N, Hubaud JC, Peyrot V, Parrain JL. Caulerpenyne–colchicine hybrid: Synthesis and biological evaluation. Bioorg Med Chem 2006; 14:5540-8. [PMID: 16714115 DOI: 10.1016/j.bmc.2006.04.024] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2006] [Revised: 04/13/2006] [Accepted: 04/20/2006] [Indexed: 10/24/2022]
Abstract
The synthesis of an analog of caulerpenyne having a trimethoxyaryl moiety was achieved in 11% overall yield over 11 steps. Its biological activity has been evaluated as inhibitor of in vitro tubulin polymerization or angiogenesis.
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Affiliation(s)
- Julien Bourdron
- UMR-CNRS 6178 SymBio, équipe Synthèse par voie Organométallique, Université Paul Cézanne (Aix-Marseille III), Marseille, France
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173
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Tsuchikawa H, Matsushita N, Matsumori N, Murata M, Oishi T. Synthesis of 28-19F-amphotericin B methyl ester. Tetrahedron Lett 2006. [DOI: 10.1016/j.tetlet.2006.06.159] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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174
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Gais HJ, Kramp GJ, Wolters D, Reddy LR. Development of a Common Fully Stereocontrolled Access to the Medicinally Important and Promising Prostacyclin Analogues Iloprost, 3-Oxa-Iloprost and Cicaprost. Chemistry 2006; 12:5610-7. [PMID: 16708414 DOI: 10.1002/chem.200600187] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
We describe new fully stereocontrolled syntheses of the prostacyclin analogues iloprost (2), the most active component of the drugs Ilomedin and Ventavis, and 3-oxa-iloprost (3), a derivative that is expected to have a significantly higher metabolic stability than 2 perhaps allowing an oral application. The syntheses are based on the same strategy and chiral bicyclic building block as used in the synthesis of cicaprost (4), the third most potent analogue that exhibits, besides prostacyclin-like activities, antimetastatic activities. Reaction of the enantiopure C6-C13 bicyclic aldehyde 17 with Cl(3)CCOOH/Cl(3)CCOONa afforded trichlorocarbinol 24 which was converted via mesylate 25 to the C6-C14 bicyclic alkyne 9. The palladium-catalysed hydrostannylation of alkyne 9 gave with high regio- and stereoselectivity the alkenylstannane 26, Sn/Li exchange of which afforded the E-configured alkenyllithium derivative 8. Coupling of the C6-C14 building block 8 with the enantiopure C15-C20 building block, the N-methoxyamide 7, gave the C6-C20 bicyclic ketone 6 in high yield without epimerisation at C16. The configuration at C15 of iloprost (2) and 3-oxa-iloprost (3) was established through a highly diastereoselective reduction of ketone 6 with catecholborane and the chiral oxazaborolidine 28 which furnished alcohol (15S)-29. The highly stereoselective conversions of alcohol (15S)-29 to iloprost (2) and 3-oxa-iloprost (3), which include as key stereoselective steps an olefination with a chiral phosphonoacetate and a copper-mediated allylic alkylation, have already been described.
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Affiliation(s)
- Hans-Joachim Gais
- Institut für Organische Chemie der Rheinisch-Westfälischen Technischen Hochschule (RWTH) Aachen, Landoltweg 1, 52056 Aachen, Germany.
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175
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Nicolaou KC, Brenzovich WE, Bulger PG, Francis TM. Synthesis of iso-epoxy-amphidinolide N and des-epoxy-caribenolide I structures. Initial forays. Org Biomol Chem 2006; 4:2119-57. [PMID: 16729126 DOI: 10.1039/b602020h] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Two strategies for the projected total synthesis of the phenomenally potent antitumour macrolides amphidinolide N (1) and caribenolide I (2) are described. The title compounds are introduced as challenging and unique targets for chemical synthesis, and their retrosynthetic analysis is presented. The synthesis of the four defined key building blocks (10, 39, 67 and 72), required for the construction of amphidinolide N (1), in their enantiomerically pure forms, is described, followed by the coupling of 10, 39 and 72 through hydrazone alkylation processes to generate the complete C6-C29 carbon framework of the target compound (1). Fusion of the remaining C1-C5 sector (72) onto the molecule by metathesis-based methods was unsuccessful, resulting in the adoption of a second-generation strategy which called for the employment of one of the array of palladium-catalysed cross-coupling reactions to generate the C5-C6 carbon-carbon bond. Vinyl bromide 125, representing the C6-C29 skeleton of caribenolide I (2), was prepared through the sequential alkylation of hydrazone 10 with bromide 116 and iodide 55, but failed to engage in the appropriate cross-coupling reaction with a variety of C1-C4 partners. Despite these setbacks, the information gleaned from these endeavours was to prove invaluable in laying the foundation for the eventual successful approach to the macrocyclic structures of amphidinolide N (1) and caribenolide I (2).
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Affiliation(s)
- K C Nicolaou
- Department of Chemistry and Skaggs Institute for Chemical Biology, Scripps Research Institute, La Jolla, California 92037, USA.
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176
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Lee K, Gallagher WP, Toskey EA, Chong W, Maleczka RE. One-pot Pd-catalyzed hydrostannation/Stille reaction with acid chlorides as the electrophiles. J Organomet Chem 2006. [DOI: 10.1016/j.jorganchem.2005.11.041] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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177
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Anwar U, Fielding MR, Grigg R, Sridharan V, Urch CJ. Palladium catalysed tandem cyclisation–anion capture processes. Part 8 : In situ and preformed organostannanes. Carbamyl chlorides and other starter species. J Organomet Chem 2006. [DOI: 10.1016/j.jorganchem.2005.11.045] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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178
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Lee T, Kang HR, Kim S, Kim S. Facile one-pot syntheses of bromoacetylenes from bulky trialkylsilyl acetylenes. Tetrahedron 2006. [DOI: 10.1016/j.tet.2006.02.016] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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179
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Abstract
[reaction: see text] An efficient synthesis of the C(11)-C(29) fragment 31 of amphidinolide F has been accomplished via a diastereoselective [3 + 2]-annulation reaction of allylsilane 5 and ethyl glyoxylate to prepare the key tetrahydrofuran 15 and a highly stereoselective methyl ketone aldol reaction to generate the C(11)-C(16) segment.
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Affiliation(s)
- J Brad Shotwell
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, USA
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180
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Niess B, Hartung IV, Haustedt LO, Hoffmann HMR. Synthesis of a Tetradehydro-Disorazole C1. European J Org Chem 2006. [DOI: 10.1002/ejoc.200500675] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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181
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Zhang H, Padwa A. An efficient synthesis of (+/-)-Lycoricidine featuring a Stille-IMDAF cycloaddition cascade. Org Lett 2006; 8:247-50. [PMID: 16408886 PMCID: PMC2587426 DOI: 10.1021/ol052524f] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
[reaction: see text] A highly efficient total synthesis of (+/-)-Lycoricidine is described. The synthesis features the ready preparation of the Lycoricidine skeleton by a Stille-IMDAF cycloaddition cascade. The resulting cycloadduct is then used for the stereocontrolled installation of the other functionality present in the C-ring of the target molecule.
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Affiliation(s)
- Hongjun Zhang
- Department of Chemistry, Emory University, Atlanta, Georgia 30322 USA
| | - Albert Padwa
- Department of Chemistry, Emory University, Atlanta, Georgia 30322 USA
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182
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Booker JEM, Boto A, Churchill GH, Green CP, Ling M, Meek G, Prabhakaran J, Sinclair D, Blake AJ, Pattenden G. Approaches to the quaternary stereocentre and to the heterocyclic core in diazonamide A using the Heck reaction and related coupling reactions. Org Biomol Chem 2006; 4:4193-205. [PMID: 17312976 DOI: 10.1039/b609604b] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In model studies towards the quaternary centre at the heart of diazonamide A (early structure 2; revised structure 1), cyclisations of the alkene-substituted iodoaryls 4, 13, 18 and 23, under Heck reaction conditions, were shown to lead to the corresponding benzodihydrofuran 5, benzofuranone 14 and the oxindoles 19 and 24 respectively, in 50-80% yield. Further manipulation of the benzodihydrofuran 5 then led to the intermediates 30, 33 and 39, which make up parts of the oxazole-indole heterocyclic core in diazonamide A. Attempts to perform a corresponding 13-exo-trig Heck cyclisation from the precursor 46a, prepared from 44 and 45, leading to 47 were not successful. A similar outcome was obtained during attempts to effect Heck cyclisations from the ester 57 and the related ether 59. Treatment of the chromene-substituted iodoaryl 62 with Pd(OAc)2, PPh3 and Ag2CO3 led to the spirocycle 64 as a crystalline solid. X-Ray crystal structure analysis established that the quaternary centre in 64 had the same configuration as that present in diazonamide A (1).
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Affiliation(s)
- James E M Booker
- School of Chemistry, The University of Nottingham, Nottingham, NG7 2RD, UK
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183
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Mitchell IS, Pattenden G, Stonehouse J. A total synthesis of the antitumour macrolide rhizoxin D. Org Biomol Chem 2005; 3:4412-31. [PMID: 16327903 DOI: 10.1039/b507570j] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An enantioselective synthesis of rhizoxin D, isolated from the plant pathogenic fungus Rhizopus chinensis, is described. The overall strategy is based on elaboration of the delta-lactone-substituted vinyl stannane and the phosphonate-substituted vinyl iodide, followed by their coupling to the core 16-membered macrolide via a sequential intermolecular Horner-Wadsworth-Emmons olefination, leading to (50), and by an intramolecular Stille reaction. The triene oxazole-containing side chain in rhizoxin D is then introduced using the phosphine oxide in an E-selective Horner-Wittig reaction with the macrolide aldehyde.
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Affiliation(s)
- Ian S Mitchell
- School of Chemistry, The University of Nottingham, Nottingham, UK, NG7 2RD
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184
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Abstract
[reactions: see text] [(Ph3P)CuH]6 effectively catalyzes the hydrostannation of activated alkynes with exclusive regioselectivity for alpha-stannation. Syn hydrostannation is observed exclusively for alkynoates. Anti or syn hydrostannation adducts are obtained as products for alkynone substrates.
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Affiliation(s)
- Lai To Leung
- Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, PR China
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185
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Affiliation(s)
- Fen-Er Chen
- Department of Chemistry, Fudan University, Shanghai, Peoples Republic of China
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186
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Abstract
The asymmetric total synthesis of (-)-reveromycin A is described. The key steps involved a Lewis acid catalyzed inverse electron demand hetero-Diels-Alder reaction followed by hydroboration/oxidation to afford the spiroketal core 4 in a highly stereoselective manner and introduction of the C18 hemisuccinate by high-pressure acylation.
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Affiliation(s)
- Mariana El Sous
- School of Chemistry, The University of Melbourne, Victoria 3010, Australia
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187
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Smith AB, Razler TM, Ciavarri JP, Hirose T, Ishikawa T. (+)-Phorboxazole A Synthetic Studies. A Highly Convergent, Second Generation Total Synthesis of (+)-Phorboxazole A. Org Lett 2005; 7:4399-402. [PMID: 16178543 DOI: 10.1021/ol051584i] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
[structure: see text] A second generation total synthesis of the potent antitumor agent (+)-phorboxazole A (1) has been achieved. The cornerstone of this approach comprises a more convergent strategy, involving late-stage Stille union of a fully elaborated C(1-28) macrocycle with a C(29-46) side chain. The second generation synthesis entails the longest linear sequence of 24 steps, with an overall yield of 4.2%.
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Affiliation(s)
- Amos B Smith
- Department of Chemistry, Monell Chemical Senses Center, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
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188
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Rupnicki L, Urbańczyk-Lipkowska Z, Stępień A, Cmoch P, Pianowski Z, Staliński K. New distannanes containing the chiral 2-(4-isopropyl-2-oxazolinyl)-5-phenyl ligand. J Organomet Chem 2005. [DOI: 10.1016/j.jorganchem.2005.03.068] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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189
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Nielsen TE, Quement SL, Juhl M, Tanner D. Cu-mediated Stille reactions of sterically congested fragments: towards the total synthesis of zoanthamine. Tetrahedron 2005. [DOI: 10.1016/j.tet.2005.06.005] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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190
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van Summeren RP, Feringa BL, Minnaard AJ. New approaches towards the synthesis of the side-chain of mycolactones A and B. Org Biomol Chem 2005; 3:2524-33. [PMID: 15999184 DOI: 10.1039/b505980a] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
New approaches towards the synthesis of the C1'-C16' side-chain of mycolactones A and B from Mycobacterium ulcerans are reported. Chiral building block 4 (Fig. 2) with the correct stereochemistry was obtained starting from naturally occurring monosaccharides, i.e. D-glucose or L-rhamnose. The polyunsaturated moiety 3 was synthesized in only 3 steps from 2,4-dimethylfuran. The building blocks were connected through a Sonogashira coupling resulting in the fast and convergent assembly of an 8,9-dehydro analogue 2 of the side-chain of mycolactones A and B. The synthesis of 1 is at this stage hampered by the lack of a selective partial hydrogenation protocol for alkynes embedded in a conjugated system. Alternative strategies involving palladium catalyzed sp2-sp2 coupling between C7' and C8' or C9' and C10' (Fig. 1) were also explored.
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Affiliation(s)
- Ruben P van Summeren
- Department of Organic and Molecular Inorganic Chemistry, Stratingh Institute, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands
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191
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Balduzzi S, Brook MA, McGlinchey MJ. Diastereoselective Addition of Allyl- and Crotylstannanes to Dicobalt-Complexed Acetylenic Aldehydes. Organometallics 2005. [DOI: 10.1021/om050019g] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Sonya Balduzzi
- Department of Chemistry, McMaster University, Hamilton, Ontario, Canada L8S 4M1, and Department of Chemistry, University College Dublin, Belfield, Dublin 4, Ireland
| | - Michael A. Brook
- Department of Chemistry, McMaster University, Hamilton, Ontario, Canada L8S 4M1, and Department of Chemistry, University College Dublin, Belfield, Dublin 4, Ireland
| | - Michael J. McGlinchey
- Department of Chemistry, McMaster University, Hamilton, Ontario, Canada L8S 4M1, and Department of Chemistry, University College Dublin, Belfield, Dublin 4, Ireland
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192
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Lumb JP, Trauner D. Biomimetic synthesis and structure elucidation of rubicordifolin, a cytotoxic natural product from Rubia cordifolia. J Am Chem Soc 2005; 127:2870-1. [PMID: 15740120 DOI: 10.1021/ja042375g] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The biomimetic synthesis and full structural elucidation of rubicordifolin, a cytotoxic natural product isolated from Rubia cordifolia, is described.
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Affiliation(s)
- Jean-Philip Lumb
- Center for New Directions in Organic Synthesis, Department of Chemistry, University of California, Berkeley, California 94720-1460, USA
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193
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Kobayashi Y, Fukuda A, Kimachi T, Ju-ichi M, Takemoto Y. Asymmetric synthetic study of macrolactin analogues. Tetrahedron 2005. [DOI: 10.1016/j.tet.2005.01.062] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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194
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Fliegel F, Beaudet I, Watrelot-Bourdeau S, Cornet N, Quintard JP. Preparation of α-substituted γ-alkoxyallylstannanes from β-tributylstannyl acrolein acetals: scope of the method and primary rationalization of the obtained results. J Organomet Chem 2005. [DOI: 10.1016/j.jorganchem.2004.10.022] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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195
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Abstract
A concise route to the common polyketide fragment5of crocacin A-D (1-4) is presented which has previously been converted into all members of this fungicidal and cytotoxic family of dipeptidic natural products by various means. Our synthesis features asyn-selective titanium aldol reaction controlled by a valinol-derived auxiliary, a zinc-mediated, palladium-catalyzedanti-selective addition of propargyl mesylate10to the chiral aldehyde9, as well as a comparison of palladium-catalyzed Stille and Suzuki cross-coupling reactions for the formation of the diene moiety of the target.
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196
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Padwa A, Rashatasakhon P, Ozdemir AD, Willis J. A Study of Vinyl Radical Cyclization Using N-Alkenyl-7-bromo-Substituted Hexahydroindolinones. J Org Chem 2004; 70:519-28. [PMID: 15651796 DOI: 10.1021/jo048314i] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A new method for the synthesis of the octahydropyrrolo[3,2,1-ij]quinoline ring system that possesses the characteristic skeleton of the aspidosperma family of alkaloids has been developed. The method utilizes an intramolecular Diels-Alder reaction of an amido-substituted furan across a tethered indole pi-bond. To apply this strategy to the synthesis of the indole alkaloid spegazzinidine, it was necessary to address the problem of assembling the final D-ring of the pentacyclic skeleton. Radical cyclization of a model N-allyl-7-bromo-3a-methylhexahydroindolinone system was found to preferentially lead to the 6-endo-trig cyclization product, with the best yield being obtained under high dilution conditions. The six-membered cyclized product is generated through two reaction pathways: (a) 6-endo-trig ring closure and (b) rearrangement of an intermediate methylene-cyclopentyl radical obtained by 5-exo-trig cyclization. A number of related 7-bromo-substituted hexahydroindolinones containing tethered olefinic groups were prepared and found to undergo efficient cyclization under both radical and palladium-mediated reaction conditions. Vinyl radical cyclization with several N-butenyl-substituted systems afforded a mixture of 6-exo and 7-endo cyclization products. A protocol to introduce an ethyl substituent into the C20-position of the aspidospermidine skeleton was also developed.
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Affiliation(s)
- Albert Padwa
- Department of Chemistry, Emory University, Atlanta, Georgia 30322, USA.
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197
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Petri AF, Bayer A, Maier ME. Total Synthesis of Apicularen A through Transannular Pyran Formation. Angew Chem Int Ed Engl 2004. [DOI: 10.1002/ange.200460760] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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198
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Petri AF, Bayer A, Maier ME. Total Synthesis of Apicularen A through Transannular Pyran Formation. Angew Chem Int Ed Engl 2004; 43:5821-3. [PMID: 15523724 DOI: 10.1002/anie.200460760] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Andreas F Petri
- Institut für Organische Chemie, Universität Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
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199
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Abstract
The antimitotic natural product disorazole C1 was isolated in 1994 from the fermentation broth of the myxobacterium Sorangium cellulosum. We have developed a highly convergent and stereoselective total synthesis of this compound which establishes its relative and absolute configuration. Key features of our synthesis include a highly convergent strategy and selective functional group manipulations that minimize decomposition of the sensitive polyene macrodiolide.
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Affiliation(s)
- Peter Wipf
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, USA.
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200
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Domínguez M, Alvarez R, Martras S, Farrés J, Parés X, de Lera AR. Synthesis of ring-oxidized retinoids as substrates of mouse class I alcohol dehydrogenase (ADH1). Org Biomol Chem 2004; 2:3368-73. [PMID: 15534715 DOI: 10.1039/b411585f] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Ring-oxidized retinoids have been synthesized stereoselectively using the Stille cross-coupling reaction. Kinetic constants of mouse class I alcohol dehydrogenase (ADH1) with these retinoids were determined.
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Affiliation(s)
- Marta Domínguez
- Departamento de Química Orgánica, Universidade de Vigo, 36200 Vigo, Spain.
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