- Enantioselective synthesis and determination of the absolute configuration of the male sex pheromone of the parasitoid wasp: Urolepis rufipes
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Males of the parasitoid wasp Urolepis rufipes use 2,6-dimethyl-7-octene-1,6-diol as a sex pheromone to attract virgin females. Herein, we determine the absolute configuration of the pheromone to be (2S,6S)-2,6-dimethyl-7-octene-1,6-diol (2S,6S-6) and present a stereoselective synthesis of the natural enantiomer of this new linalool derivative. In addition, we show that female wasps respond to the natural 2S,6S-6 stereoisomer while 2R,6S-6 is behaviorally inactive.
- Grimm, Christopher,Melnik, Kristina,Ruther, Joachim,Schulz, Stefan,Wittbrodt, Johannes
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supporting information
p. 3463 - 3465
(2020/06/10)
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- Isobenzofurans as Synthetic Intermediates: Synthesis and Biological Activity of 8-epi-(–)-Ajudazol B
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Ajudazol B is a polyketide secondary metabolite, isolated from the myxobacterium Chondromyces crocatus, that exhibits potent biological activity. Herein, we report a convergent total synthesis of 8-epi-(–)-ajudazol B. The key step is a regio-selective alk
- Adair, Liam,Egan, Ben A.,Pearson, Colin M.,Lopez-Gonzalez, Ricardo,Kuchar, Michal,Mendoza-Mendoza, Artemio,Prunet, Jo?lle,Marquez, Rodolfo
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supporting information
p. 6661 - 6672
(2020/10/15)
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- Structure-Elucidating Total Synthesis of the (Polyenoyl)tetramic Acid Militarinone C §
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The (polyenoyl)tetramic acid militarinone C (1) heads a family of seven members. Before our work, the configuration of C-5 was unknown whereas the configurations of C-8′ and C-10′ were either (R,R) or (S,S). We synthesized the four stereoisomers of constitution 1, which conform with these insights. This included cross-coupling both enantiomers of the western building block (8) with both enantiomers of the eastern building block (9). The specific rotations of the resulting 1 isomers suggested that natural 1 is configured like the coupling partners (S)-8 and (R,R)-9. This conclusion was corroborated by degrading natural 1 to alcohol 35 and by proving its configurational identity with synthetic (R,R)-35.
- Brückner, Reinhard,Drescher, Christian,Hamburger, Matthias,Keller, Morris,Potterat, Olivier
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supporting information
(2020/03/30)
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- Evolution of a Polyene Cyclization Cascade for the Total Synthesis of (?)-Cyclosmenospongine
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We report a full account on the development of a unique cationic polyene cyclization for the total synthesis of the tetracyclic meroterpenoid (?)-cyclosmenospongine. A highly convergent three-component coupling strategy enabled rapid access to individual cyclization precursors that were tested for their reactivity. The successful transformation generates three rings and sets four consecutive stereocenters in a single operation proceeding in a highly efficient manner to give exclusively the trans-decalin framework. In addition, we found that the enol ether geometry and the relative configuration of C3 and C8 are crucial for the success of the polyene cyclization.
- Speck, Klaus,Magauer, Thomas
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supporting information
p. 1157 - 1165
(2017/02/05)
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- METHODS FOR PRODUCING BERAPROST AND ITS DERIVATIVES
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The present invention is directed to methods for preparing Beraprost and novel synthetic intermediates for Beraprost. In one aspect, a process is provided to produce a pharmaceutical compound represented by the general Formula (I) via a radical cyclization route. The process is completed in fewer steps than the known synthetic methods and may be conducted to prepare commercially useful quantities. In another aspect, synthetic methods are provided for producing Beraprost and its derivatives,, which are stereoselective, efficient, scalable and economical. In another aspect, substantially isomerically pure compounds and intermediates are produced by the above processes.
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Paragraph 0064; 0067; 0068; 00128
(2015/12/08)
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- Total synthesis of virgatolide B
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The first total synthesis of the benzannulated spiroketal virgatolide A is presented. Key features include sp3-sp2 Suzuki coupling of an enantiomerically enriched β-trifluoroboratoamide and an aryl bromide, regioselective intramolecular carboalkoxylation, and a 1,3-anti-selective Mukaiyama aldol reaction followed by global deprotection/cyclization with regioselectivity governed by internal hydrogen bonding.
- Hume, Paul A.,Furkert, Daniel P.,Brimble, Margaret A.
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supporting information
p. 4588 - 4591
(2013/09/24)
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- Enantioselective total synthesis of pladienolide B: A potent spliceosome inhibitor
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An enantioselective and convergent total synthesis of pladienolide B (1) is described. Pladienolide B binds to the SF3b complex of a spliceosome and inhibits mRNA splicing activity. The synthesis features an epoxide opening reaction, an asymmetric reduction of a β-keto ester, and a cross metathesis strategy for the side chain synthesis.
- Ghosh, Arun K.,Anderson, David D.
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supporting information
p. 4730 - 4733
(2013/01/15)
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- Xestoproxamines A-C from Neopetrosia proxima. assignment of absolute stereostructure of bis-piperidine alkaloids by integrated degradation-CD analysis
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The complete stereostructures of xestoproxamines A-C, from the Bahamian sponge Neopetrosia proxima, were assigned from spectroscopic analysis, including MS, 2D NMR, and integrated degradation-CD analysis. Two new CD application protocols are described for defining absolute configuration: one for allylic methyl groups in branched chains and a second for the heterocyclic core bis-piperidine with specific applicability to other members of this class alkaloids - known for their stereoheterogeneity - and tertiary cyclic amines in general.
- Morinaka, Brandon I.,Molinski, Tadeusz F.
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experimental part
p. 430 - 440
(2011/05/13)
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- Synthesis and structure-activity correlation of natural-product inspired cyclodepsipeptides stabilizing F-actin
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The fundamental role played by actin In the regulation of eukaryotic cell maintenance and motility renders it a primary target for small-molecule intervention. in this arena, a class of potent cytotoxic cyclodepsipeptide natural products has emerged over the last quarter-century to stimulate the fields of biology and chemistry with their unique actin-stabilizing properties and complex peptide-polyketide hybrid structures. Despite considerable research effort, a structural basis for the activity of these secondary metabolites remains elusive, not least for the lack of high-resolution structural data and a reliable synthetic route to diverse compound libraries. in response to this, an efficient solid-phase approach has been developed and successfully applied to the total synthesis of Jasplakinolide and chondramide C and diverse analogues. The key macrocylization step was realized using ruthenium-catalyzed ring-closing metathesis (RCM) that in the course of a library synthesis produced discernible trends in metathesis reactivity and E/Z-selectivity, After optimization, the RCM step could be operated under mild conditions, a result that promises to facilitate the synthesis of more extensive analogue libraries for structure-function studies. The growth inhibitory effects of the synthesized compounds were quantified and structure-activity correlations established which appear to be in good alignment with relevant biological data from natural products. in this way a number of potent unnatural and simplified analogues have been found. Furthermore, potentially important stereochemical and structural components of a common pharmacophore have been identified and rationalized using molecular modeling. These data will guide in-depth mode-of-action studies, especially into the relationship between the cytotoxicity of these compounds and their actin-perturbing properties, and should inform the future design of simplified and functionalized actln stabilizers as well.
- Tannert, Rene,Milroy, Lech-Gustav,Ellinger, Bernhard,Hu, Tai-Shan,Arndt, Hans-Dieter,Waldmann, Herbert
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supporting information; experimental part
p. 3063 - 3077
(2010/05/15)
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- General synthesis of highly functionalized cyclopentane segments for the preparation of jatrophane diterpenes
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Short and efficient syntheses of two diastereomeric cyclopentane segments present in most jatrophane diterpenes were achieved. Key steps are a stereoselective C-2 elongation, an RCM, and a hydroboration reaction. An orthogonal protecting group methodology
- Lentsch, Christoph,Rinner, Uwe
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supporting information; experimental part
p. 5326 - 5328
(2010/02/28)
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- Leucascandrolide A: Synthesis and Related Studies
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The total synthesis of the biologically active marine natural product leucascandrolide A is reported. A convergent strategy is employed, allowing for the rapid assembly of the macrolide moiety. Key steps of our approach include the diastereoselective addi
- Fettes, Alec,Carreira, Erick M.
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p. 9274 - 9283
(2007/10/03)
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- Stereoselective syntheses of epothilones A and B via nitrile oxide cycloadditions and related studies
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The expedient and fully stereocontrolled synthesis of epothilones A and B are described. The routes described make extensive study of nitrile oxide cycloadditions as surrogates for aldol addition reactions and have led to the realization of a highly convergent synthesis based on the Kanemasa hydroxyl-directed nitrile oxide cycloaddition. As well, our synthetic efforts have led to the development of new reaction methodologies and served as the proving ground for several modern methods for asymmetric carbon-carbon bond formation.
- Bode,Carreira
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p. 6410 - 6424
(2007/10/03)
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- Estrogen receptor subtype-selective ligands: Asymmetric synthesis and biological evaluation of cis- and trans-5,11-dialkyl-5,6,11,12- tetrahydrochrysenes
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We have recently reported that racemic 5,11-cis-diethyl-5,6,11,12- tetrahydrochrysene-2,8-diol (THC, rac-2b) acts as an agonist on estrogen receptor alpha (ERα) and as a complete antagonist on estrogen receptor beta (ERβ) (Sun et al. Endocrinology 1999, 1
- Meyers, Marvin J.,Jun, Sun,Carlson, Kathryn E.,Katzenellenbogen, Benita S.,Katzenellenbogen, John A.
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p. 2456 - 2468
(2007/10/03)
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- Sex pheromone of the pine sawfly, Macrodiprion nemoralis. Stereoselective synthesis of the sixteen stereoisomers of 3,7,9-trimethyl-2-tridecyl acetate
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The sixteen stereoisomers of 3,7,9-trimethyl-2-tridecyl acetate (5Ac) were prepared individually, each in over 99.5% stereochemical purity. The syntheses were based on the ring opening of a pure enantiomer of cis-3,4-dimethyl-γ-butyrolactone using a pure stereoisomer of 1-lithio-2,4-dimethyloctane, the two stereogenic centres of which were introduced with high selectivity by alkylations of the amide enolates from the appropriate enantiomers of pseudoephedrine. (2S,3R,7R,9S)-3,7,9-Trimethyl-2-tridecyl acetate (SRRS-5Ac) has recently been found to be the major component of the female sex pheromone of Macrodiprion nemoralis (Hymenoptera: Diprionidae). A synthetic method for the preparation of a sixteen isomer mixture of 5Ac is also presented. This mixture has been found to be biologically active in field tests.
- Karlsson, Staffan,Hedenstroem, Erik
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p. 620 - 630
(2007/10/03)
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