- Formal Synthesis of (±)-Aplykurodinone-1 Based on the Indium-Catalyzed Conia-Ene Reaction
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A concise formal synthesis of (±)-aplykurodinone-1 starting from a commercially available material and based on the indium-catalyzed Conia-ene reaction has been accomplished. The synthesis features a Riley selenium dioxide oxidation, a Krapcho dealkoxycarbonylation, and a ring-closing metathesis approach. The synthetic strategy was also supported by a Saegusa oxidation and a classic Michael 1,4-conjugate addition.
- Wang, Xiaoji,Zhou, Yi,Xiao, Hesheng,Ou, Wentao,Pang, Yiying,Li, Wang,Wang, Liping,Huang, Shuangping
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Read Online
- Synthesis of α-methylene propellanone via the strategic employment of metal-mediated cyclisation chemistry
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Biologically active α-methylenene propellanone has been synthesised in 12 steps in an overall yield of 11%. The key step of the synthesis, an intramolecular Pauson-Khand reaction, proceeds in good yield under alkyl sulfide promotion conditions, to furnish
- Kerr, William J.,Morrison, Angus J.,Paterson, Laura C.
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Read Online
- Catalytic use of chiral phosphine ligands in asymmetric Pauson-Khand reactions
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Catalytic asymmetric Pauson-Khand reactions with chiral bidentate phosphines as ligands have been successfully accomplished. The catalytic use of (S)-BINAP as a ligand was demonstrated to be the most effective in the cobalt-catalyzed reactions of 1,6-enyn
- Hiroi, Kunio,Watanabe, Takashi,Kawagishi, Ryoko,Abe, Ikuko
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Read Online
- A Cell-Targeted Non-Cytotoxic Fluorescent Nanogel Thermometer Created with an Imidazolium-Containing Cationic Radical Initiator
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A cationic fluorescent nanogel thermometer based on thermo-responsive N-isopropylacrylamide and environment-sensitive benzothiadiazole was developed with a new azo compound bearing imidazolium rings as the first cationic radical initiator. This cationic fluorescent nanogel thermometer showed an excellent ability to enter live mammalian cells in a short incubation period (10 min), a high sensitivity to temperature variations in live cells (temperature resolution of 0.02–0.84 °C in the range 20–40 °C), and remarkable non-cytotoxicity, which permitted ordinary cell proliferation and even differentiation of primary cultured cells.
- Uchiyama, Seiichi,Tsuji, Toshikazu,Kawamoto, Kyoko,Okano, Kentaro,Fukatsu, Eiko,Noro, Takahiro,Ikado, Kumiko,Yamada, Sayuri,Shibata, Yuka,Hayashi, Teruyuki,Inada, Noriko,Kato, Masaru,Koizumi, Hideki,Tokuyama, Hidetoshi
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Read Online
- Total synthesis and structural revision of laurefurenynes A and B
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Structural reassignment: A total synthesis of the proposed structure of (-)-laurefurenynea A has been accomplished that relies on organocatalytic aldehyde α-chlorination and a flexible chlorohydrin-based strategy for stereocontrolled access to the bis-tetrahydrofuran core of the natural product. Analysis of incongruities between the 1Ha NMR spectra of synthetic and natural material led to a configurational reassignment for the natural product, which was also confirmed by total synthesis. Copyright
- Holmes, Michael T.,Britton, Robert
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Read Online
- Intramolecular heck couplings and cycloisomerizations of bromodienes and enynes with 1′,1′-disubstituted methylenecyclopropane terminators: Efficient syntheses of [3]dendralenes
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2-Bromoalka-1,n-dienes such as 9, 30 and 14 (n = 7) with tetrasubstituted methylenecyclopropane end groups, under palladium catalysis, underwent cyclization with cyclopropane-ring opening to give 2-ethenyl-3-methylene-1- cycloalkenes 41 (n = 6), 42 (n = 7
- Braese, Stefan,Wertal, Hanno,Frank, Daniel,Vidovic, Denis,De Meijere, Armin
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Read Online
- Ynonylation of Acyl Radicals by Electroinduced Homolysis of 4-Acyl-1,4-dihydropyridines
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Herein we report the conversion of 4-Acyl-1,4-dihydropyridines (DHPs) into ynones under electrochemical conditions. The reaction proceeds via the homolysis of acyl-DHP under electron activation. The resulting acyl radicals react with hypervalent iodine(III) reagents to form the target ynones or ynamides in acceptable yields. This mild reaction condition allows wider functionality tolerance that includes halides, carboxylates, or alkenes. The synthetic utility of this methodology is further demonstrated by the late-stage modification of complex molecules.
- Luo, Xiaosheng,Wang, Ping
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supporting information
p. 4960 - 4965
(2021/07/20)
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- INTRACELLULAR DELIVERY VEHICLE
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PROBLEM TO BE SOLVED: To provide a vehicle which can easily deliver a desired component or compound into a cell without preventing cell proliferation. SOLUTION: A intracellular delivery vehicle has its surface covered with positive electric charge. SELECTED DRAWING: None COPYRIGHT: (C)2020,JPOandINPIT
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Paragraph 0166; 0174-0175
(2020/08/13)
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- INTRACELLULAR DELIVERY VEHICLE
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An intracellular delivery vehicle of which surface is covered by a positive charge, an intracellular delivery complex in which a component or compound desired is loaded in the intracellular delivery vehicle, a temperature-sensitive probe comprising the intracellular delivery complex, and a method for measuring the intracellular temperature by the temperature-sensitive probe are disclosed. The intracellular delivery vehicle is useful on account of its capability of easily delivering the component or compound desired inside the cell without inhibiting cell proliferation.
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Paragraph 0296
(2019/05/18)
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- Synthesis and biological evaluation of 12-, 13-, 14-membered macrolides and open chain 2,6-trans-disubstituted dihydropyran analogues for aspergillides
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Stereoselective synthesis of twenty (three 12-, five 13- and twelve 14-membered) macrolides and seventeen functionalized 2,6-trans-disubstituted dihydropyran derivatives have been achieved. The key reactions include an Achmatowicz rearrangement, Ferrier-type alkynylation, Yamaguchi macrolactonization and Lindlar's hydrogenation. Biological screening of the synthesised compounds showed moderate activity against human cancer cell-lines.
- Pabbaraja, Srihari,Gantasala, Naresh,Ydhyam, Sridhar,Namballa, Hari Krishna,Gundeboina, Subhashini,Lambu, Mallikharjuna R.,Meena, Sanjeev,Datta, Dipak
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supporting information
p. 2570 - 2576
(2018/05/30)
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- BISARYL HETEROCYCLES AS NRF2 ACTI
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The present invention relates to bisaryl heterocycle compounds, methods of making them, pharmaceutical compositions containing them and their use as NRF2 activators. In particular, the invention relates to bisaryl heterocycles of Formula (I),
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Page/Page column 235; 236
(2018/07/05)
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- HETEROARYLCARBOXAMIDE DERIVATIVES AS PLASMA KALLIKREIN INHIBITORS
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Heteroarylcarboxamides of formula (I), wherein A, T, R1, R2 and R3 are as defined in the specification and the claims, and pharmaceutically acceptable salts thereof can be used in methods for the treatment of diseases which can be influenced by inhibition of plasma kallikrein.
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Page/Page column 57
(2018/11/22)
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- Two-fold tandem acyl-group shift/cyclization via gold catalysis
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A complex cascade involving allendiynes in the presence of a cationic gold catalyst is described. The process features two sequential acyl-group shift/cyclization steps eventually delivering a bicyclic furan derivative from the acyclic precursor. A contro
- Simonneau, Antoine,Maestri, Giovanni,Fensterbank, Louis,Malacria, Max
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p. 287 - 296
(2014/05/20)
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- Practical methods for the synthesis of trifluoromethylated alkynes: Oxidative trifluoromethylation of copper acetylides and alkynes
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Two practical and complementary methods are reported for the synthesis of trifluoromethylated alkynes. The first one, a mix-and-stir process, is based on the oxidative trifluoromethylation of readily available and bench-stable copper acetylides while the second one, which displays a broad substrate scope and has several advantages over existing procedures, is based on the oxidative copper-catalyzed direct trifluoromethylation of terminal alkynes. Both reactions provide user-friendly processes for the synthesis of trifluoromethylated acetylenes which can be easily obtained from readily available starting materials.
- Tresse, Cedric,Guissart, Celine,Schweizer, Stephane,Bouhoute, Yassine,Chany, Anne-Caroline,Goddard, Mary-Lorene,Blanchard, Nicolas,Evano, Gwilherm
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supporting information
p. 2051 - 2060
(2014/07/07)
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- Enantiospecific intramolecular heck reactions of secondary benzylic ethers
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Enantioenriched methylenecyclopentanes are synthesized by stereospecific, nickel-catalyzed Heck cyclizations of secondary benzylic ethers. The reaction proceeds in high yield and enantiospecificity for benzylic ethers of both π-extended and simple arenes. Ethers with pendant 1,2-disubstituted olefins form trisubstituted olefins with control of both absolute configuration and alkene geometry. Diastereoselective synthesis of a polycyclic furan is demonstrated.
- Harris, Michael R.,Konev, Mikhail O.,Jarvo, Elizabeth R.
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supporting information
p. 7825 - 7828
(2014/06/23)
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- Dendritic fluoroalcohols as catalysts for alkene epoxidation with hydrogen peroxide
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Cooperativity is the key for mild catalytic epoxidation: The immobilization of fluoroalcohols on dendritic polyglycerol (by "click chemistry") provides organocatalysts that can form multiple hydrogen bonds. The epoxidation of alkenes with aqueous hydrogen peroxide proceeds efficiently in the presence of dendritic fluoroalcohol catalysts. The supported catalysts can be separated by membrane filtration and reused. Copyright
- Berkessel, Albrecht,Kraemer, Jan,Mummy, Florian,Neudoerfl, Joerg-M.,Haag, Rainer
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p. 739 - 743
(2013/02/23)
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- Stereoselectivity in trimethylenemethane (TMM) diyl mediated cycloaddition reaction to angularly fused triquinanes
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A thorough study on the diastereoselectivity in the TMM diyl mediated [2+3] cycloaddition reaction of monosubstituted linear substrates to form angularly fused triquinanes was carried out. Substitution at position 3 provided complete diastereoselectivity,
- Yoon, Yeokwon,Kang, Taek,Lee, Hee-Yoon
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supporting information; experimental part
p. 646 - 651
(2011/10/03)
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- THERAPEUTIC COMPOUNDS
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The invention relates to novel resolvin compounds and pharmaceutical preparations thereof. The invention further relates to methods of treatment using the novel resolvin compounds of the invention.
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Page/Page column 129
(2010/04/27)
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- Click chemistry approach to new N-substituted aminocyclitols as potential pharmacological chaperones for gaucher disease
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New N-alkylaminocyclitols bearing a 1,2,3-triazole system at different positions of the alkyl chain have been prepared as potential GCase pharmacological chaperones using click chemistry approaches. Among them, compounds 1d and 1e, with the shorter spacer
- Díaz, Lucía,Bujons, Jordi,Casas, Josefina,Llebaria, Amadeu,Delgado, Antonio
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supporting information; experimental part
p. 5248 - 5255
(2010/10/19)
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- Synthesis of azide-alkyne fragments for 'click' chemical applications. formation of chiral 1,4-disubstituted-(β-alkyl) γ- 1,2,3-triazole scaffolds from orthogonally protected chiral β-alkyl-trialkylsilyl γ- Pentynyl azides and chiral β-alkyl γ- Pentynyl-alcohols
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A library of chiral γ-pentynyl alcohols and γ-pentynyl azides was made using the SuperQuat auxiliary. Coupling of the free alkynes with the azides by Huisgen 1,3-dipolar cycloaddition provided chiral oligomeric 1,4-disubstituted-1,2,3-triazoles as possible peptidomimetic compounds.
- Montagnat, Oliver D.,Lessene, Guillaume,Hughes, Andrew B.
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body text
p. 1541 - 1549
(2011/09/16)
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- Cycloisomerization of aromatic homo and bis-homopropargylic alcohols via catalytic ru vinylidenes: Formation of benzofurans and isochromenes
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Ru-catalyzed cycloisomerizations of aromatic homo- and bis-homopropargylic alcohols effectively afford benzofurans and isochromenes. These processes proved to be chemo- and regioselective (5-, and 6-endo cyclizations) derived from key Ru vinylidene intermediates. The presence of an amine/ammonium base-acid pair is crucial for the catalytic cycle.
- Varela-Fernandez, Alejandro,Gonzalez-Rodriguez, Carlos,Varela, Jesus A.,Castedo, Luis,Saa, Carlos
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supporting information; experimental part
p. 5350 - 5353
(2009/12/30)
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- Synthesis of (4R,15R,16R,21S)- and (4R,15S,16S,21S)-rollicosin, squamostolide, and their inhibitory action with bovine heart mitochondrial complex I
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A convergent stereoselective synthesis of (4R,15R,16R,21S)- and (4R,15S,16S,21S)-rollicosin and squamostolide was accomplished via a Pd-catalyzed cross-coupling reaction. The inhibitory activity of these compounds was examined with bovine heart mitochondrial NADH-ubiquinone oxidoreductase. These compounds showed a remarkably weak inhibitory activity compared to ordinary acetogenins such as bullatacin. Our results indicate that to maintain potent inhibitory effect, the hydroxylated lactone cannot substitute for the hydroxylated mono- or bis-THF rings with a long alkyl chain that can be seen in ordinary acetogenins.
- Makabe, Hidefumi,Kimura, Yuka,Higuchi, Masaharu,Konno, Hiroyuki,Murai, Masatoshi,Miyoshi, Hideto
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p. 3119 - 3130
(2007/10/03)
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- Deoxynojirimycin analogues and their uses as glucosylceramidase inhibitors
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The invention provides a new class of deoxynojirimycin analogues, or pharmaceutically acceptable salts thereof which can suitably be used for the treatment of a disease selected from the group consisting of insulin resistance, Gauger disease, inflammatory
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Page/Page column 8; 28
(2008/06/13)
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- Synthesis of (4R,15R,16R,21S)- and (4R,15S,16S,21S)-rollicosin
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A convergent synthesis of (4R,15R,16R,21S)-rollicosin (1) and (4R,15S,16S,21S)-rollicosin (2) was accomplished. Hydroxy lactone 6a and/or 6b were synthesized from 4-pentyn-1-ol, and α,β-unsaturated lactone 7 was synthesized from γ-lactone 8 and 5-hexen-1-
- Makabe, Hidefumi,Higuchi, Masaharu,Konno, Hiroyuki,Murai, Masatoshi,Miyoshi, Hideto
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p. 4671 - 4675
(2007/10/03)
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- Syntheses of seven-membered rings: Ruthenium-catalyzed intramolecular [5+2] cycloadditions
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The Ru-catalyzed intramolecular [5+2] cycloaddition of cyclopropylenynes is investigated with respect to the regio- and diastereoselectivity as well as the functional group compatibility of the reaction. Evidence for the mechanism as occurring through a ruthenacyclopentene intermediate is elucidated from 1) the study of the diastereoselectivity of the cycloaddition; 2) the effect of variation of substituents on the regioselectivity of cyclopropyl bond cleavage in 1,2-trans- and 1,2-cis-disubstituted cyclopropanes and 3) examples that clearly do not involve ruthenacyclohexene as intermediates as products still incorporate the cyclo propyl moiety. The scope and limitations of the Ru-catalyzed cycloaddition are discussed and compared with the Rh-catalyzed reaction. The potential power of this methodology towards natural product total synthesis is demonstrated by the formation of several polycyclic systems with the chosen reaction conditions and readily available cyclopropylenyne substrates.
- Trost, Barry M.,Shen, Hong C.,Horne, Daniel B.,Toste, F. Dean,Steinmetz, Bernhard G.,Koradin, Christopher
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p. 2577 - 2590
(2007/10/03)
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- Efficient construction of the bicyclo[5.3.0]decenone skeleton based on the Rh(I)-catalyzed allenic Pauson-Khand reaction
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A reliable procedure for constructing a bicyclo[5.3.0]deca-1,7-dien-9-one ring system by rhodium-catalyzed Pauson-Khand reaction (PKR) of allenynes with a sulfonyl group has been developed. Investigation of the rhodium-catalyzed PKR on 19 examples of 1,2-nonadien-8-yne derivatives demonstrated that (i) acceptable yields could be consistently achieved through the proper choice of the rhodium catalyst ([RhCl(CO)2]2 or [RhCl(CO)dppp]2) depending on the starting allenyne and that (ii) an ester functionality as well as hydroxy and siloxy groups could be tolerated in this rhodium-catalyzed PKR.
- Mukai, Chisato,Nomura, Izumi,Kitagaki, Shinji
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p. 1376 - 1385
(2007/10/03)
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- A New, Simple, and Selective Palladium-Catalyzed Cleavage of Triethylsilyl Ethers
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(Equation Presented) A simple procedure for the cleavage of triethylsilyl (TES) ethers in the presence of 10 wt % Pd/C in methanol or 95% ethanol is reported. This method allows selective removal of alkyl TES ethers in the presence of aromatic TES ethers or tert-butyldimethylsilyl (TBS) protecting groups.
- Rotulo-Sims, Delphine,Prunet, Joelle
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p. 4701 - 4704
(2007/10/03)
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- Relative asymmetric induction in the intramolecular reaction between alkynes and cyclopropylcarbene-chromium complexes: Stereocontrolled synthesis of five-membered rings fused to oxygen heterocycles
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Synthesis of cyclopentenone derivatives fused to oxygen heterocycles by means of the intramolecular coupling of alkynes and cyclopropylcarbene- chromium complexes has been examined for a variety of cases in which the tethering chain features a stereogenic
- Yan,Zhu,Matasi,Herndon
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p. 1291 - 1301
(2007/10/03)
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- Pyryliumolates. III. Synthesis of Annulated Benzotropolones
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Dirhodiumtetraacetate catalyzed nitrogen extrusion from diazocarbonyl compounds (2a-f, 19c, 23d-f, 25b) yields benzopyryliumolates (3), which were trapped intramolecularly in situ to give tetracyclic adducts (4a, 5a-d, 20, 24a-c, 26). Starting with 5a and 5d annulated benzotropolones (12a, d) are accessible.
- Plueg, Carsten,Friedrichsen, Willy,Debaerdemaeker, Tony
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p. 205 - 216
(2007/10/03)
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- A convenient synthesis of alkynylsilanes by silylation of copper(I) alkynides
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Alkynylation of chlorosilanes with copper(I) alkynides takes place smoothly in the presence of triphenylphosphine, N, N, N′, N′-tetramethylethylenediamine, or zinc powder to give a variety of alkynylsilanes in good yields.
- Sugita, Hikaru,Hatanaka, Yasuo,Hiyama, Tamejiro
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p. 379 - 380
(2007/10/03)
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- New cobalt-catalyzed cycloisomerization of ε-acetylenic β-keto esters. Application to a powerful cyclization reactions cascade
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The full details of investigations into the cobalt(I)-catalyzed ene type reaction of ε-acetylenic β-keto esters to form highly functionalized methylenecyelopentanes are described. The observed regio-, chemo-, and stereoselectivities support a process of cycloisomerization which controls the relative stereochemistry of two contiguous stereogenic centers. An efficient route to the basic skeleton of the phyllocladane family has been achieved via a one-pot sequence of cyclizations: ene type, [2 + 2 + 2], [4 + 2]. This new cascade created six carbon-carbon bonds and four rings in a totally stereoselective manner from an easily accessible acyclic polyunsaturated precursor.
- Cruciani, Paul,Stammler, Robert,Aubert, Corinne,Malacria, Max
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p. 2699 - 2708
(2007/10/03)
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- N-Alkenyl nitrone dipolar cycloaddition routes to piperidines and indolizidines. Part 8. The scope of tandem reactions involving hydroxylamine-alkyne cyclisations
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A tandem sequence of hydroxylamine-alkyne cyclisation/1,3-dipolar cycloaddition, provides useful entry into tricyclic systems of type 4. The scope of such reactions is explored in this paper. A novel cascade cyclisation of N-hydroxypyrrolidines of type 26 and 28 involving hydroxylamine-alkyne cyclisation, Cope elimination and 1,3-dipolar cycloaddition is also reported.
- Davison, Edwin C.,Forbes, Ian T.,Holmes, Andrew B.,Warner, Jacqueline A.
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p. 11601 - 11624
(2007/10/03)
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- Silylation of 1-Alkynes with Chlorosilanes Promoted by Zinc: Preparation of Alkynylsilanes in a Single Step
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The direct silylation of 1-alkynes with chlorosilanes smoothly takes place in the presence of zinc powder in acetonitrile, giving good yields of alkynylsilanes.The reactions are tolerant of a wide range of functionalities such as carboxylic acid, ester, alcohol, and chlorine in the 1-alkynes.
- Sugita, Hikaru,Hatanaka, Yasuo,Hiyama, Tamejiro
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p. 2769 - 2772
(2007/10/02)
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- Pd-catalyzed cycloisomerization to 1,2-dialkylidenecycloalkanes. 1
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Enhancing synthetic efficiency requires the development of synthetic reactions that, to the extent possible, are simple additions wherein everything else is required only in catalytic amounts. The Alder ene reaction constitutes a classical reaction that meets this requirement that has much unrealized potential. A transition-metal-catalyzed version helps to increase that potential by permitting this reaction to proceed under mild conditions. A significant benefit of transition metal catalysis is the feasibility of diverting the reaction along pathways not feasible under thermal conditions. The synthesis of 1,3-dienes rather than 1,4-dienes is a very important diversion because of the utility of 1,3-dienes as reaction partners in the Diels-Alder reaction, another highly atom economical process. A catalyst derived from palladium acetate cycloisomerizes 1,6- and 1,7-enynes to dialkylidenecyclopentanes and -cyclohexanes. 1,3-Diene formation is favored over the Alder ene process by both steric and electronic effects. The reaction is highly chemoselective - tolerating a wide diversity of functionality including hydroxyl groups, ketones, esters, alkynyl and enol ethers, alkynyl and vinyl silanes, and enones. Many of the substrates are available by palladium-catalyzed alkylation reactions - highlighting the effectiveness of palladium catalyzed methodology in organic synthesis. The atom-economical nature of these reactions combined with the Diels-Alder reaction permit butadiene and dimethyl propargylmalonate to be molded into a polyhydro-as-indacene. The mechanism of this reaction may involve a tautomerization of an enyne-Pd(+2) complex to a pallada(+4)cyclopentene intermediate as a key step.
- Trost, Barry M.,Tanoury, Gerald J.,Lautens, Mark,Chan, Chuen,MacPherson, David T.
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p. 4255 - 4267
(2007/10/02)
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- Carbocyclic ring expansion reactions via free radical pathways - Part III
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The free radical ring expansion methodology recently described1, leading to the formation of medium sized ring ketones from cyclohexanone precursors has been applied to different side chains and ring sizes. In addition precursors based on lactone rings have been prepared and subjected to radical forming reaction conditions.
- Baldwin, Jack E.,Adlington, Robert M.,Singh, Rajinder
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p. 3385 - 3412
(2007/10/02)
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- Radical Cyclization of (Bromomethyl)dimethylsilyl Propargyl Ethers. Regio-, Chemo-, and Stereoselectivity
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Radical cyclization of (bromomethyl)dimethylsilyl propargyl ether derivatives 1 is a powerful reaction with a high degree of regio-, chemo-, and stereoselectivity.Trisubstituted olefins 3, cyclopentene derivatives 5, and diquinane system 7j are obtained in good yields by a judicious choice of unsaturated substituents.Triquinane frameworks could be obtained stereoselectively from a suitable acyclic substrate of type 1 in a one-pot reaction.First attempts have not yet allowed us to aim at this goal due to interesting (1,5) hydrogen transfers.Moreover, we have intercepted, for the first time, the α-cyclopropyl radical which is involved in the Storck-Beckwith mechanism of the 5-versus 6-membered ring formation in the vinyl radical cyclization.
- Journet, Michel,Malacria, Max
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p. 3085 - 3093
(2007/10/02)
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- Simple preparation of α-bromo acyl silanes α-ketoacyl silanes and α-ketoesters from silyl acetylenes
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α-Bromo- and α-keto-acyl silanes may simply and efficiently be prepared in short reaction schemes from silyl acetylenes; α-ketoacyl silanes are also implicated in a one-pot synthesis of α-ketoesters from silyl acetylenes.
- Bulman Page, Philip C.,Rosenthal, Stephen
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p. 2573 - 2586
(2007/10/02)
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- Synthetic Radical Chemistry. Total Synthesis of (+/-)-Isoamijiol
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A total synthesis of the dolastane diterpene (+/-)-isoamijiol (1), found in the brown seaweed Dictyota linearis, is described.The synthesis, which starts from cyclopentanone, uses just seven carbon-to-carbon bond forming reactions, four of which involve free radical intermediates.The 5,7-ring fused (azulene) portion in (1) was elaborated by an intramolecular -photocycloaddition (17)>-intermolecular reductive coupling (29)>cyclobutane fragmentation (15)>sequence, and the 6-ring in compuond (1) was annulated via intramolecular reductive coupling of the terminal acetylenic ketone intermediate (14) .Oxidation of compound (38), using catalytic selenium dioxide in the presence of t-butyl hydroperoxide, then produced (+/-)-isoamijiol which showed spectral data identical with naturally derived material.
- Begley, Michael J.,Pattenden, Gerald,Robertson, Graeme M.
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p. 1085 - 1094
(2007/10/02)
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- SEQUENTIAL CLAISEN-ENE APPROACH TO CARBOCYCLIZATION: A NEW ENTRY TO A STEROID C/D RING SYNTHON
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A new and facile entry to a steroid C/D ring synthon is described which relies on the sequential combination of the Claisen rearrangement with the intramolecular ene reaction involving an acetylenic bond with methoxycarbonyl group as the enophile.
- Takahashi, Kazuhiko,Mikami, Koichi,Nakai, Takeshi
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p. 5277 - 5280
(2007/10/02)
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- Studies on Synthesis of Linear Aliphatic Compounds. Part 2. The Realisation of a Strategy for Repeated Molecular Doubling.
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Routes from C11 and C12 starting-materials, obtainable free from near homologues, to compounds of doubled chain length have been explored as approaches to the synthesis of n-paraffins and of terminally mono- or bi-functional derivatives.Acetylene alkylation routes lead to problems with prtotecting groups, but the use of the Wittig reaction provides a method of molecular doubling convenient for repeated use, with formation of chain-lengths rising in a geometrical progression.The general problems inherent in the synthesis of very long-chain paraffins are discussed, earlier work is reviewed, and criteria for success are suggested.A useful protecting group for hydroxyl, the tri-p-tolylmethyl(trimtyl) ether, is described.
- Igner, Eva,Paynter, Oliver I.,Simmonds, Derek J.,Whiting, Mark C.
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p. 2447 - 2454
(2007/10/02)
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- A Selective Method for Oxygen Deprotection in Bistrimethylsilylated Terminal Alkynols
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A selective method for oxygen deprotection of bistrimethylsilylated ω-alkynols is described using sulfonic acid type exchange resins in ether solvent.The method offers the advantages of selectivity toward the silicon-oxygen bond, easier monitoring of the reaction and workup, and higher yields (>75percent).Comparisons are made between standart aqueous acid procedures and a series of resins.
- Bunce, Richard A.,Hertzler, Donald V.
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p. 3451 - 3453
(2007/10/02)
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- Alkaloid synthesis via the intramolecular imidate methylide 1,3-dipolar cycloaddition reaction
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A concise synthesis for the neurotoxic physostigmine alkaloid d,l-eserethole is described which relys upon an intramolecular cycloaddition reaction involving a "non-stabilized" imidate methylide and an unactivated alkene. The facility of this cyclization
- Smith, Richard,Livinghouse, Tom
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p. 3559 - 3568
(2007/10/02)
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