- Asymmetric total synthesis of naturally occurring spirocyclic tetranorsesquiterpenoid lanceolactone A
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Asymmetric total synthesis of naturally occurring γ-butenolide containing [4.4]spiro-tetrahydrofuran lanceolactone A has been reported in the present work. Bimetallic ("Pd-Cu") cascade cyclization was the crucial reaction employed for the construction of the γ-butenolide framework of the natural product. Subsequently, iodocyclization and reductive deiodination through a transfer hydrogenation reaction were applied to access the target molecule in an efficient manner.
- Acharyya, Ranjan Kumar,Nanda, Samik
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p. 5027 - 5035
(2018/07/25)
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- Studies toward the Total Synthesis of the Marine Macrolide Salarin C
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A convergent strategy for the synthesis of dideoxysalarin C (3) as a potential intermediate for the total synthesis of the marine macrolide salarin C (1) is described. The macrolactone core of 3 was assembled by Suzuki coupling between alkyl iodide 9 and
- Schrof, Raffael,Altmann, Karl-Heinz
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supporting information
p. 7679 - 7683
(2018/12/11)
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- 7-Step total synthesis of (+)-EBC-329: Photoisomerisation reveals new: Seco -casbane family member
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The first seco-casbane, EBC-329, isolated from the Australian rainforest, was synthesised from (+)-2-carene in seven steps. This endeavour not only established the absolute stereochemical assignment as (8R,9S)-EBC-329, but also identified, via photoisomer
- Vanden Berg, Timothy J.,Pinkerton, David M.,Williams, Craig M.
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supporting information
p. 7102 - 7105
(2017/09/07)
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- Palladium-catalyzed stereoretentive olefination of unactivated C(sp3)-H bonds with vinyl iodides at room temperature: Synthesis of β-vinyl α-amino acids
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A method is reported for palladium-catalyzed N-quinolyl carboxamide-directed olefination of the unactivated C(sp3)-H bonds of phthaloyl alanine with a broad range of vinyl iodides at room temperature. This reaction represents the first example of the stereoretentive installation of multisubstituted terminal and internal olefins onto unactivated C(sp3)-H bonds. These methods enable access to a wide range of challenging β-vinyl α-amino acid products in a streamlined and controllable fashion, beginning from simple precursors.
- Wang, Bo,Lu, Chengxi,Zhang, Shu-Yu,He, Gang,Nack, William A.,Chen, Gong
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supporting information
p. 6260 - 6263
(2015/02/19)
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- Chemistry and biology of deoxynyboquinone, a potent inducer of cancer cell death
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Deoxynyboquinone (DNQ) is a potent antineoplastic agent with an unknown mechanism of action. Here we describe a facile synthetic route to this anthraquinone, and we use this material to determine the mechanism by which DNQ induces death in cancer cells. DNQ was synthesized in seven linear steps through a route employing three palladium-mediated coupling reactions. Experiments performed on cancer cells grown in hypoxia and normoxia strongly suggest that DNQ undergoes bioreduction to its semiquinone, which then is re-oxidized by molecular oxygen, forming superoxide that induces cell death. Furthermore, global transcript profiling of cells treated with DNQ shows elevation of transcripts related to oxidative stress, a result confirmed at the protein level by Western blotting. In contrast to most other antineoplastic agents that generate reactive oxygen species (ROS), DNQ potently induces death of cancer cells in culture, with IC50 values between 16 and 210 nM. In addition, unlike the experimental therapeutic elesclomol, DNQ is still able to induce cancer cell death under hypoxic conditions. This mechanistic understanding of DNQ will allow for a more comprehensive evaluation of the potential of direct ROS generation as an anticancer strategy, and DNQ itself has potential as a novel anticancer agent.
- Bair, Joseph S.,Palchaudhuri, Rahul,Hergenrother, Paul J.
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supporting information; experimental part
p. 5469 - 5478
(2010/07/03)
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- Iodoxolone-based hypervalent iodine reagents
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Image Persented The fast access to simple (Z)-3-iodo acrylic acid derivatives which can be easily oxidized to the corresponding hypervalent iodine(III) reagents is described. They can be used for various reactions with superior or similar reactivity as conventional hypervalent iodine(III) reagents.
- Shah, Azhar-Ul-Haq A.,Khan, Zulfiqar A.,Choudhary, Naila,Lohoelter, Christine,Schaefer, Sascha,Marie, Guillaume P.L.,Farooq, Umar,Witulski, Bernhard,Wirth, Thomas
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supporting information; experimental part
p. 3578 - 3581
(2011/02/22)
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- Extension of the library of biologically active γ-alkylidene butenolides
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γ-Alkylidene butenolides bearing a deoxyriboside, a steroid, and a metallocene moiety were synthesized by stereoselective sequential cross-coupling lactonization procedure from the corresponding functionalized terminal alkynes with 3-iodopropenoic acids.
- Novak, Petr,Pour, Milan,Spulak, Marcel,Votruba, Ivan,Kotora, Martin
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experimental part
p. 3465 - 3472
(2009/05/27)
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- Stereoselective hydrohalogenation of alkynoic acids and their esters in ionic liquids
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A novel procedure is described for the hydrohalogenation of alkynoic acids and their esters using N-alkylpyridinium ionic liquids. Hydrohalogenating agents were prepared by mixing N-alkylpyridinium halides with an equimolar amount of trifluoroacetic acid.
- Salazar, Jose,Fernandez, Francys,Restrepo, Jelem,Lopez, Simon E.
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p. 170 - 172
(2008/02/12)
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- Stereoselective synthesis of trienoic acids: Synthesis of retinoic acids and analogues
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Stereoselective construction of conjugated trienoic acids was achieved through two successive Stille reactions, the first step consisting of the coupling of (E)-1,2-bis(tributylstannyl)ethene and tributylstannyl (Z)- or (E)-3-iodoalk-2-enoates. Two different routes were used for the second step: (1) cross-coupling of the stannyldienoic acid reagents and vinyl iodides, or (2) cross-coupling of vinylstannane reagents and the tributylstannyl 5-iodopenta-2,4-dienoates generated by iododestannylation of stannyldienes. Vinylstannanes synthesized by stannylmetalation of the Negishi dienyne derived from β- or α-ionone and safranal thus provided access to stereodefined retinoic acids. Some retinoid and yne analogues were also prepared by Sonogashira coupling. Georg Thieme Verlag Stuttgart.
- Abarbri, Mohamed,Parrain, Jean-Luc,Duchene, Alain,Thibonnet, Jerome
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p. 2951 - 2970
(2008/02/05)
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- Palladium-catalysed cross-coupling of iodovinylic acids with organometallic reagents. Selective synthesis of 3,3-disubstituted prop-2-enoic acids
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3,3-Disubstituted prop-2-enoic acids were selectively prepared in good yields under mild experimental conditions via palladium-catalysed cross-coupling of 3-substituted 3-iodobut-2-enoic acids with miscellaneous organometallic reagents using dichlorobis(acetonitrile)palladium(II) as catalyst and DMF as solvent.
- Abarbri, Mohamed,Thibonnet, Jér?me,Parrain, Jean-Luc,Duchêne, Alain
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p. 543 - 551
(2007/10/03)
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- Total synthesis of the epidermal growth factor inhibitor (-)-reveromycin B
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The total synthesis of the epidermal growth factor inhibitor reveromycin B (2) in 25 linear steps from chiral methylene pyran 13 is described. The key steps involved an inverse electron demand hetero-Diels-Alder reaction between dienophile 13 and diene 12 to construct the 6,6-spiroketal 11 which upon oxidation with dimethyldioxirane and acid catalyzed rearrangement gave the 5,6-spiroketal aldehyde 9. Lithium acetylide addition followed by oxidation/reduction and protective group manipulation provided the reveromycin B spiroketal core 8 which was converted into the reveromycin A (1) derivative 6 in order to confirm the stereochemistry of the spiroketal segment. Introduction of the C1-C10 side chain began with sequential Wittig reactions to form the C8-C9 and C7-C6 bonds, and a tin mediated asymmetric aldol reaction installed the C4 and C5 stereocenters. The final key steps to the target molecule 2 involved a Stille coupling to introduce the C21-C22 bond, succinoylation, selective deprotection, oxidation, and Wittig condensation to form the final C2-C3 bond. Deprotection was effected by TBAF in DMF to afford reveromycin B (2) in 72% yield.
- Cuzzupe,Hutton,Lilly,Mann,McRae,Zammit,Rizzacasa
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p. 2382 - 2393
(2007/10/03)
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- Palladium-catalyzed cross-coupling of 3-iodobut-3-enoic acid with organometallic reagents. Synthesis of 3-substituted but-3-enoic acids
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3-Substituted but-3-enoic acids were obtained in good yields under mild experimental conditions by palladium-catalyzed cross-coupling of 3-iodobut-3-enoic acid with organozinc or organotin compounds using PdCl2(MeCN)2 as catalyst and DMF as solvent.
- Abarbri,Parrain,Kitamura,Noyori,Duchene
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p. 7475 - 7478
(2007/10/03)
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- Total synthesis of (+)-crocacin C.
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The first asymmetric synthesis of (+)-crocacin C (3) is described which served to confirm the absolute configuration of this compound. The key step in the sequence was the stereoselective assembly of the (E,E)-diene amide side chain by a Stille cross-coup
- Feutrill,Lilly,Rizzacasa
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p. 3365 - 3367
(2007/10/03)
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- Stereoselective synthesis of all-trans-, (13Z)- and (9-nor)-retinoic acids via Stille reaction
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Stereoselective construction of retinoic acid and certain analogues were achieved through two successive Stille reactions. First, the coupling of (E)- 1,2-bis(tributylstannyl)ethene and (Z)- or (E)-tributylstannyl 3-iodoalk-2- enoates was performed followed by iododestannylation. The second step involved another vinyltin which was synthesised by stannylmetallation of the Negishi dienyne derived from β-ionone.
- Thibonnet, Jér?me,Abarbri, Mohamed,Duchêne, Alain,Parrain, Jean-Luc
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p. 141 - 143
(2007/10/03)
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- Stereospecific synthesis of (Z) or (E)-3-methylalk-2-enoic acids
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The palladium catalysed coupling of organozinc or organotin reagents with 3-iodobut-2(or 3)-enoic acid is stereoselective and affords Z (or E)-3-methylalk-2-enoic acids. The method was applied to the synthesis of the E and Z stereoisomers of ocimenones and pseudo-tagetones.
- Abarbri,Parrain,Duchene
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p. 2469 - 2472
(2007/10/02)
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