- Synthetic spirocyclic endoperoxides: New antimalarial scaffolds
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Here we report the development of a straightforward synthetic procedure for the preparation of spirocyclic endoperoxides as synthetic analogues of the natural product dihydroplakortin. The peroxides presented here are more potent antiplasmodials than dihydroplakortin itself and we proved for the first time their antimalarial activity in vivo. This journal is
- Brindisi, Margherita,Gemma, Sandra,Kunjir, Sanil,Di Cerbo, Luisa,Brogi, Simone,Parapini, Silvia,D'Alessandro, Sarah,Taramelli, Donatella,Habluetzel, Annette,Tapanelli, Sofia,Lamponi, Stefania,Novellino, Ettore,Campiani, Giuseppe,Butini, Stefania
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- CATHODIC PROMOTION OF HORNER REACTION
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It has been established that the electrolysis of α-substituted phosphonates (I) on Pt or glassy carbon cathodes involves the cleavage of activated C-H bond with the formation of the carbanion (II) which further reacts with the carbonyl compounds (III) to form olefines (IV) in satisfactory yields.
- Niyazymbetov, M. E.,Petrosyan, V. A.,Keitel, I.,Costisella, B.,Schwarz, K. H.
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- Cyclopropanation in Vinyl Radical Cyclizations: the Importance of Structural Constraints.
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Cyclopropanation has been observed as sole reaction path in the vinyl radical cyclization of bicyclic olefins 1a and 1b.Additional models have been prepared to study the influence of structural parameters on the origin of this unusual reactivity.Structural constraints in the intermediate homoallyl radical formed stand out as the dominating factor in this case.
- Denis, Real C.,Rancourt, Jean,Ghiro, Elise,Boutonnet, Francois,Gravel, Denis
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- Benzotriazole-assisted β-lithiation of vinyl ethers
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Benzotriazole-assisted β-deprotonation of (α-benzotriazolylvinyl) ethers occurs stereoselectively at the cis position as shown by quenching with a variety of electrophiles. Semiempirical calculations of the lithiated enol ethers by PM3 and MNDO methods disclosed a higher stabilization for the cis-isomers over the corresponding trans-isomers
- Katritzky,Katritzky, Alan R.,Ignatchenko,Ignatchenko, Alexey V.,Lan,Lan, Xiangfu,Lang,Lang, Hengyuan,Stevens,Stevens, Christian V.,Opitz,Opitz, Andreas,Koch,Koch, Rainer,Anders,Anders, Ernst
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- Claisen rearrangement based methodology for the spiroannulation of a cyclopentane ring. Formal total synthesis of (±)-acorone and isoacorones
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A Claisen rearrangement based methodology for spiroannulation of a cyclopentane ring to cyclic precursors and its application in the formal total synthesis of acorones 1 is described. Thus, Claisen rearrangement of 2-cycloalkylideneethanols 12 with 2-methoxypropene and a catalytic amount of mercuric acetate generates 4,4-substituted hex-5-en-2-ones 13. Ozonolytic cleavage of the terminal olefin in the enones 13 and intramolecular aldol condensation of the resulting keto-aldehydes 14 furnishes the spiroannulated compounds 15. (C) 2000 Elsevier Science Ltd.
- Srikrishna,Praveen Kumar
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- HETEROCYCLIC COMPOUNDS AS INHIBITORS OF HPK1
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This disclosure relates to heterocyclics as inhibitors of HPK1, in particular relates to a compound of Formula I or a pharmaceutically acceptable salt thereof, and a pharmaceutical composition comprising said compound that useful for treatment of HPK1 mediated diseases and conditions such as cancer. (I)
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Page/Page column 154-155
(2021/01/29)
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- Synthesis and Exploration of Abscisic Acid Receptor Agonists Against Dought Stress by Adding Constraint to a Tetrahydroquinoline-Based Lead Structure
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New oxotetrahydroquinolinyl- and oxindolinyl sulfonamides interacting with RCAR/(PYR/PYL) receptor proteins were identified as lead structures against drought stress in crops starting from protein docking studies of a sulfonamide lead structure, followed by in-depth SAR studies. Optimized five to six step synthetic approaches via substituted amino oxo-tetrahydro-quinolines and amino oxo-indolines as essential intermediates gave access to the envisaged oxo-tetrahydroquinolinyl and oxindolinyl sulfonamides. Whilst oxo-tetrahydroquinolinyl sulfonamides with additional carbon substituents or spiro-cycloalkyl groups exhibited only low to moderate target affinities, the corresponding spiro-oxindolinyl and oxo-tetrahydroquinolinyl sulfonamides carrying optimized N-substituents revealed strong interactions with RCAR/(PYR/PYL) receptor proteins in Arabidopsis thaliana. Remarkably, the in vitro activity observed for these new compounds was on the same level as observed for the naturally occurring plant hormone in line with strong efficacy against drought stress in-vivo (canola and wheat as broad-acre crops).
- Baltz, Rachel,Bojack, Guido,Dittgen, Jan,Fischer, Christian,Frackenpohl, Jens,Freigang, J?rg,Getachew, Rahel,Grill, Erwin,Helmke, Hendrik,Hohmann, Sabine,Lange, Gudrun,Lehr, Stefan,Porée, Fabien,Schmidt, Jana,Schmutzler, Dirk,Yang, Zhenyu
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supporting information
p. 3442 - 3457
(2021/06/25)
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- Visible-Light Mediated Hydrosilylative and Hydrophosphorylative Cyclizations of Enynes and Dienes
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Described herein is a visible-light mediated intermolecular radical cyclization approach to access heterocycles. Heteroatom radicals, such as silicon and phosphorus atom radicals, were generated via direct hydrogen atom abstraction by the photoexcited catalyst species with hydro-silanes and phosphine oxides. The radical addition/cyclization/HAT (hydrogen atom transfer) reaction sequences of 1,6-enynes and 1,6-dienes were highly efficient delivering the desired heterocycles in good yields.
- Chen, Xiaoyun,Hou, Hong,Shi, Yaocheng,Xu, Yue,Yan, Chaoguo,Yang, Haibo,Zhu, Shaoqun
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supporting information
(2020/03/04)
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- Visible-Light-Promoted Intramolecular α-Allylation of Aldehydes in the Absence of Sacrificial Hydrogen Acceptors
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We report herein an unprecedented protocol for radical cyclization of aldehydes with pendant alkenes via synergistic photoredox, cobaloxime, and amine catalysis. The transformation was achieved in the absence of external oxidants, providing a variety of 5-, 6-, and 7-membered ring products with alkene transposition in satisfactory yields. The reaction exhibits wide functional group compatibility and occurs under mild conditions with extrusion of H2.
- Liu, Feng,Liu, Jia-Li,tu, Jia-Lin
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supporting information
p. 7369 - 7372
(2020/10/05)
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- Reusable and highly enantioselective water-soluble Ru(II)-Amm-Pheox catalyst for intramolecular cyclopropanation of diazo compounds
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A reusable and highly enantioselective catalyst for the intramolecular cyclopropanation of various diazo ester and Weinreb amide derivatives was developed. The reactions catalyzed by a water-soluble Ru(II)-Amm-Pheox catalyst proceeded smoothly at room temperature, affording the corresponding bicyclic cyclopropane ring-fused lactones and lactams in high yields (up to 99%) with excellent enantioselectivities (up to 99% ee). After screening of various catalysts, the Ru(II)-Amm-Pheox complex having an ammonium group proved to be crucial for the intramolecular cyclopropanation reaction in a water/ether biphasic medium. The water-soluble catalyst could be reused at least six times with little loss in yield and enantioselectivity.
- Mandour, Hamada S.A.,Nakagawa, Yoko,Tone, Masaya,Inoue, Hayato,Otog, Nansalmaa,Fujisawa, Ikuhide,Chanthamath, Soda,Iwasa, Seiji
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supporting information
p. 357 - 363
(2019/02/20)
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- A Sequential Acyl Thiol-Ene and Thiolactonization Approach for the Synthesis of δ-Thiolactones
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A novel strategy for the synthesis of δ-thiolactones from inexpensive and readily available ?-unsaturated esters has been developed. This strategy incorporates a radical acyl thiol-ene reaction as the key C-S bond forming step. Cyclization is achieved via a Steglich-type thiolactonization of 5-mercaptopentanoic acids. We report the facile and scalable synthesis of δ-thiolactones in moderate to good yield under mild reaction conditions with tolerance for a range of functional groups.
- McCourt, Ruairí O.,Scanlan, Eoin M.
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supporting information
p. 3460 - 3464
(2019/05/10)
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- Synthesis of Cyclobutene-Fused Eight-Membered Carbocycles through Gold-Catalyzed Intramolecular Enyne [2+2] Cycloaddition
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Cationic gold(I) complexes with hollow-shaped triethynylphosphine ligands efficiently catalyzed intramolecular [2+2] cycloaddition of 1,9-enynes to afford cyclobutene-fused eight-membered carbocycles that were difficult to synthesize by other catalytic systems. Various 1,9-enynes with carbon linkers with or without a fused ring underwent efficient [2+2] cycloaddition with 5 mol% of the Au catalyst bearing the triarylmethyl-end-capped triethynylphosphine in CH2Cl2 at rt in the presence of MS 4A as an additive. More challenging 1,9-enyne substrates with fully saturated acyclic carbon linkers underwent eight-membered ring formation at 60 °C in ClCH2CH2Cl in the absence of MS 4A, forming monocyclic 1,3-dienes as major products. (Figure presented.).
- Iwai, Tomohiro,Ueno, Masahiro,Okochi, Hiori,Sawamura, Masaya
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supporting information
p. 670 - 675
(2017/12/26)
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- Transition Metal Free Cycloamination of Prenyl Carbamates and Ureas Promoted by Aryldiazonium Salts
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Upon treatment with aryldiazonium salts, prenyl carbamates and ureas undergo redox-neutral azocycloamination. In general, N-aryl O-prenyl carbamates cyclize in a photocatalytic reaction with visible light and an organic dye. With electron-deficient diazonium salts, electronic matching with an electron-rich N-aryl substituent results in a reaction proceeding in the ground state, without either light or photocatalyst. Cyclic voltammetry suggests that this radical reaction is initiated by hydrogen-atom abstraction mediated by an aryl radical, followed by a radical addition cascade and proton-coupled hole propagation. The reaction proceeds at room temperature in short reaction times, and a range of functional groups is tolerated.
- Abrams, Roman,Lefebvre, Quentin,Clayden, Jonathan
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supporting information
p. 13587 - 13591
(2018/09/25)
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- Rapid Access to Thiolactone Derivatives through Radical-Mediated Acyl Thiol-Ene and Acyl Thiol-Yne Cyclization
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A new synthetic approach to thiolactones that employs an efficient acyl thiol-ene (ATE) or acyl thiol-yne (ATY) cyclization to convert unsaturated thiocarboxylic acid derivatives into thiolactones under very mild conditions is described. The high overall yields, fast kinetics, high diastereoselectivity, excellent regiocontrol, and broad substrate scope of these reaction processes render this a very useful approach for diversity-oriented synthesis and drug discovery efforts. A detailed computational rationale is provided for the observed regiocontrol.
- McCourt, Ruairi O.,Dénès, Fabrice,Sanchez-Sanz, Goar,Scanlan, Eoin M.
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supporting information
p. 2948 - 2951
(2018/05/28)
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- Transition-Metal-Free Formylation of Allylzinc Reagents Leading to α-Quaternary Aldehydes
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The first example of formylation of allylzinc reagents using S-phenyl thioformate is presented. The reaction proceeded under mild conditions without any transition-metal catalyst, forming quaternary carbon centers with reactive functionalities, such as formyl and vinyl groups. Moreover, Barbier-type formylation of an allylic bromide with a sterically demanding thioformate was achieved. As a preliminary result, asymmetric formylation was conducted using a menthol-derived chiral thioformate.
- Haraguchi, Ryosuke,Kusakabe, Akinori,Mizutani, Nakaba,Fukuzawa, Shin-Ichi
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supporting information
p. 1613 - 1616
(2018/03/23)
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- USE OF SUBSTITUTE OXO TETRAHYDROQUINOLINE SULFONAMIDES OR SALTS THEREOF FOR RAISING STRESS TOLERANCE OF PLANTS
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The invention relates to the use of substituted oxotetrahydroquinolinylsulfonamides or salts thereof where the radicals in the general formula (I) correspond to the definitions given in the description, for enhancing stress tolerance in plants to abiotic stress, and/or for increasing plant yield.
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Paragraph 0201
(2017/02/28)
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- Copper-catalyzed [1,2]-rearrangements of allylic iodides and aryl α-diazoacetates
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The [1,2]- and [2,3]-rearrangements of iodonium ylides are synthetically useful reactions for the generation of functionalized α-iodoesters. Allylic iodides are coupled with α-diazoesters in the presence of a copper catalyst and a ligand to generate iodonium ylides, which undergo metal-mediated rearrangements. By fine-tuning the structure of the ligand, we have reversed the regioselectivity of copper-catalyzed reactions of iodonium ylides from [2,3]- to [1,2]-rearrangements with the use of alternate bipyridine ligands. The preference for [1,2]-rearrangements was further improved by using bulky aryl α-diazoester substrates. Several α-iodoesters with a diverse range of functional groups were generated in good yields (up to 88% yield) and high regioselectivities (up to >95:5 regioisomeric ratio). A deuterium-labeled substrate was utilized to gain insight into the mechanism of the reaction.
- Xu, Bin,Gartman, Jackson A.,Tambar, Uttam K.
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p. 4150 - 4159
(2017/06/29)
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- Copper-Catalyzed Enantio-, Diastereo-, and Regioselective [2,3]-Rearrangements of Iodonium Ylides
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The first highly enantioselective, diastereoselective, and regioselective [2,3]-rearrangement of iodonium ylides has been developed as a general solution to catalytic onium ylide rearrangements. In the presence of a chiral copper catalyst, substituted allylic iodides couple with α-diazoesters to generate metal-coordinated iodonium ylides, which undergo [2,3]-rearrangements with high selectivities (up to >95:5 r.r., up to >95:5 d.r., and up to 97 % ee). The enantioenriched iodoester products can be converted stereospecifically into a variety of onium ylide rearrangement products, as well as compounds that are not accessible by classical onium ylide rearrangements.
- Xu, Bin,Tambar, Uttam K.
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supporting information
p. 9868 - 9871
(2017/08/08)
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- Preparation of polycyclic compounds by intramolecular photospirocyclization and photocycloaddition reactions of 4-alkenyl-1-cyanonaphthalene derivatives
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Photoreactions of 4-pentenyl-1-cyanonaphthalenes yield spirocyclic products along with [4?+?2] cycloadducts. Photoreactions of 5-phenyl derivatives produce a product having tricyclo[6.3.0.01,4]undecadiene skeleton. Formation of angular triquinanes takes place in photoreactions of cycloalkene-linked cyanonaphthalenes. The observation demonstrates that π–π arene ring interactions, steric hindrance, and suitable locations of reaction sites in syn and anti singlet exciplexes govern the modes followed in intramolecular photoreactions of 4-alkenyl-1-cyanonaphthalenes.
- Maeda, Hajime,Wada, Hidenori,Mukae, Hirofumi,Mizuno, Kazuhiko
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- The synthesis of α,α-disubstituted α-amino acids via ichikawa rearrangement
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An approach to α,α-disubstituted α-amino acids is reported. The key step is allyl cyanate-to-isocyanate rearrangement. As demonstrated, the resultant allyl isocyanates can be directly trapped with various nucleophiles, for instance, alcohols, amines, and organometallic reagents, to provide a broad range of N-functionalized allylamines. The developed method has been successfully applied in the synthesis of two bioactive peptides: 2-aminoadamantane-2-carboxylic acid derived P2X7-evoked glutamate release inhibitor and 4-amino-tetrahydropyranyl-4-carboxylic acid derived dipeptide GSK-2793660, which is currently in clinical trials as cathepsin C inhibitor for the treatment of cystic fibrosis, noncystic fibrosis bronchiectasis, ANCA-associated vasculitis and bronchiectasis.
- Szczes?niak, Piotr,Pieczykolan, Micha?,Stecko, Sebastian
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p. 1057 - 1074
(2016/02/19)
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- Pd-Catalyzed α-Selective C-H Functionalization of Olefins: En Route to 4-Imino-β-Lactams
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Pd-catalyzed α-olefinic C-H activation of simple α,β-unsaturated olefins has been developed. 4-imino-β-lactam derivatives were readily synthesized via activation of α-olefinic C-H bonds with excellent cis stereoselectivity. A wide range of heterocycles at the β-position are compatible with this reaction. The product of 4-imino-β-lactam derivatives can be readily converted to 2-aminoquinoline which exists extensively in pharmaceutical drugs and natural products.
- Kong, Wei-Jun,Liu, Yue-Jin,Xu, Hui,Chen, Yan-Qiao,Dai, Hui-Xiong,Yu, Jin-Quan
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supporting information
p. 2146 - 2149
(2016/03/05)
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- Carbene-catalyzed desymmetrization of 1,3-diols: Access to optically enriched tertiary alkyl chlorides
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The introduction of a chlorine atom to a carbon center in an enantioselective manner via conventional C-Cl bond formation is difficult. Here we report a new approach to this class of tertiary alkyl chlorides with high optical purities. Instead of forming a new C-Cl bond, our approach involves carbene-catalyzed desymmetrization of 2-chloro-1,3-diols as the key step to set up the chiral carbon center with excellent enantiomeric excess.
- Li, Bao-Sheng,Wang, Yuhuang,Proctor, Rupert S. J.,Jin, Zhichao,Chi, Yonggui Robin
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supporting information
p. 8313 - 8316
(2016/07/06)
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- Ligand-Controlled Regiodivergence in the Copper-Catalyzed [2,3]- and [1,2]-Rearrangements of Iodonium Ylides
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Despite the importance of allylic ylide rearrangements for the synthesis of complex molecules, the catalyst control of [2,3]- and [1,2]-rearrangements remains an unsolved problem. We developed the first regiodivergent [2,3]- and [1,2]-rearrangements of iodonium ylides that are controlled by copper catalysts bearing different ligands. In the presence of a 2,2′-dipyridyl ligand, diazoesters and allylic iodides react via a [2,3]-rearrangement pathway. Alternatively, a phosphine ligand favors the formation of the [1,2]-rearrangement product. A series of α-iodoesters containing a broad range of functional groups were obtained in high yields, regioselectivities, and diastereoselectivities. Deuterium-labeling studies suggest distinct mechanisms for the regioselective rearrangements.
- Xu, Bin,Tambar, Uttam K.
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supporting information
p. 12073 - 12076
(2016/09/28)
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- Titanium(IV) Chloride-Mediated Stereoselective α-Alkylidenation to Efficiently Assemble Multisubstituted 1,3-Dienes
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A direct access to multisubstituted 1,3-dienes by α-exclusive alkylidenation of crotonic derivatives has been developed. This protocol, mediated by titanium tetrachloride chelation, features excellent regio- and stereoselectivity, mild reaction conditions, easy operation and wide substrate scope. Conversions of the derived dienes to other useful molecules were also explored. (Figure presented.).
- Sun, Rengwei,Song, Wei,Ma, Chunmei,Zhang, Huiwen,Yu, Xinhong
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supporting information
p. 3977 - 3982
(2016/12/30)
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- NOVEL PROCESS FOR TOTAL SYNTHESIS OF VENLAFAXINE
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There is a need for short, resolution free asymmetric process for synthesis of one isomer of venlafaxine, (-)-venlafaxine. The invention provides a novel, short process of synthesis of (-)-venlafaxine, with yield greater than 50% and ee> 99%. This process can be used for racemic synthesis of venlafaxine with overall yield 65%.
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Paragraph 0041
(2015/05/19)
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- SUBSTITUTED PYRIMIDINE COMPOUNDS, COMPOSITIONS AND MEDICINAL APPLICATIONS THEREOF
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The present disclosure relates to pyrimidine compounds of formula (I), their stereoisomers, tautomers, pharmaceutically acceptable salts, polymorphs, solvates, and hydrates thereof. The present disclosure also relates to process of preparation of these pyrimidine compounds, and to pharmaceutical compositions containing them. The compounds of the present disclosure are useful in the treatment, prevention or suppression of diseases and disorders mediated by epidermal growth factor receptor (EGFR) family kinases.
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Paragraph 000145
(2015/03/13)
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- Dialkylzinc-mediated allylic polyfluoroarylation reaction
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Abstract We present an allylic polyfluoroarylation reaction with broad substrate scope and excellent functional group tolerance, using organozinc reagents under mild conditions. A catalytic amount of triphenylphosphine oxide efficiently promotes iodine-zinc exchange reaction between polyfluoroaryl iodide and dimethylzinc, and the resulting phosphine oxide-activated polyfluoroarylzinc undergoes substitution reaction with allylic halides to afford the corresponding polyfluoroarylated products.
- Kurauchi, Daisuke,Hirano, Keiichi,Kato, Hisano,Saito, Tatsuo,Miyamoto, Kazunori,Uchiyama, Masanobu
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supporting information
p. 5849 - 5857
(2015/08/03)
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- A protecting group free and scalable approach towards total synthesis of (-)-venlafaxine
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A protecting group free asymmetric total synthesis of (-)-venlafaxine is reported. The strategy employs Sharpless epoxidation and regio-selective epoxide ring opening by an in situ generated Gilman reagent as key steps. This paper reports a 53% overall yield in 6 steps for total synthesis of (-)-venlafaxine. This journal is the Partner Organisations 2014.
- Chavan, Subhash P.,Pawar, Kailash P.,Garai, Sumanta
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p. 14468 - 14470
(2014/04/17)
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- SUBSTITUTED ISOXAZOLE DERIVATIVES
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The present invention relates to compounds of the formula (I) wherein the substituents are defined in the claims and the specification.
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Page/Page column 211
(2014/12/12)
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- Enantioselective intramolecular aldehyde α-alkylation with simple olefins: Direct access to homo-ene products
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A highly selective method for the synthesis of asymmetrically substituted carbocycles and heterocycles from unactivated aldehyde-olefin precursors has been achieved via enantioselective SOMO-catalysis. Addition of a catalytically generated enamine radical cation across a pendent olefin serves to establish a general asymmetric strategy toward the production of a wide range of formyl-substituted rings with alkene transposition. Conceptually, this novel mechanism allows direct access to "homo-ene"-type products.
- Comito, Robert J.,Finelli, Fernanda G.,Macmillan, David W. C.
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supporting information
p. 9358 - 9361
(2013/07/26)
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- GERANYLGERANYLACETONE DERIVATIVES
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Provided herein are geranylgeranylacetone derivatives and methods of using them.
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Paragraph 0278
(2013/04/13)
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- Selectivity control by silver catalysts in the cycloisomerization of 1,6-enynes derived from propiolamides
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Silver-catalyzed cycloisomerizations of 1,6-enynes derived from propiolamides led to a selective formation of Alder-ene type 1,4-dienes. Interestingly, AgNTf2 outperformed gold or platinum catalysts in terms of selectivity and reactivity, providing the 1,4-dienes at room temperature. The presence of C(5) carbonyl group in combination with Ag salts is key to the selectivity and the β-oxo coordinated silver carbenoids were proposed as an intermediate based on the reaction profiles.
- Koo, Jaeyoung,Park, Hyun-Sub,Shin, Seunghoon
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supporting information
p. 834 - 839
(2013/02/25)
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- Catalytic, enantioselective, and highly chemoselective bromocyclization of olefinic dicarbonyl compounds
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Overriding preferences: An amine-thiocarbamate catalyst can mediate the facile, efficient, and highly enantioselective bromocyclization of olefinic 1,3-dicarbonyl compounds. In the presence of the bifunctional catalyst, the bromination occurs chemoselectively at the olefinic moiety rather than at the carbon atom in the α-position to the carbonyl units. Copyright
- Zhao, Yi,Jiang, Xiaojian,Yeung, Ying-Yeung
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supporting information
p. 8597 - 8601
(2013/09/12)
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- A newly-designed PE-supported arsine for efficient and practical catalytic Wittig olefination
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A newly designed PE-supported arsine has been developed as an excellent catalyst for catalytic Wittig-type olefination. Simple ketones, in particular inactive ketones prove to be suitable substrates for the first time. This reaction provides an easy access to di-, tri-, and tetra-substituted olefins in high yield.
- Wang, Peng,Liu, Chun-Rong,Sun, Xiu-Li,Chen, Shuai-Shuai,Li, Jun-Fang,Xie, Zuowei,Tang, Yong
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supporting information; experimental part
p. 290 - 292
(2012/01/06)
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- α,β-Unsaturated imines via Ru-catalyzed coupling of allylic alcohols and amines
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A convenient synthesis of α,β-unsaturated imines requiring only an allylic alcohol, an amine and a Ru catalyst has been developed. The use of large excesses of oxidant and the purification of sensitive intermediates can be avoided.
- Rigoli, Jared W.,Moyer, Sara A.,Pearce, Simon D.,Schomaker, Jennifer M.
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supporting information; experimental part
p. 1746 - 1749
(2012/04/23)
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- Contemporaneous dual catalysis: Chemoselective cross-coupling of catalytic vanadium-allenoate and π-allylpalladium intermediates
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This paper presents a detailed investigation of a dual catalytic system that combines a vanadium-catalyzed Meyer-Schuster rearrangement and a palladium-catalyzed allylic alkylation. The implementation of this novel reaction relies on matching the formation rates of vanadium-allenoate and π-allylpalladium intermediates with their bimolecular coupling rate in order to minimize the undesired protonation or O-alkylation of the catalytically generated intermediates. Chemoselectivity in this dual catalytic process was successfully achieved by adjusting ligand structure and catalyst loading ratios of the vanadium and palladium catalysts. A great range of coupling partners for both the propargyl alcohol and allyl carbonate components are readily accommodated in this new transformation, which in turn provides a novel avenue to a variety of α-allylated α,β-unsaturated ketones, esters, and amides in moderate to excellent isolated yields.
- Trost, Barry M.,Luan, Xinjun,Miller, Yan
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supporting information; experimental part
p. 12824 - 12833
(2011/10/05)
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- Gold-catalysed activation of epoxides: Application in the synthesis of bicyclic ketals
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Gold-catalysed generation of diol equivalents from epoxides and their intramolecular reaction with Ca≡C bonds to generate bicyclic ketals is presented. This reaction essentially involves the formation of an acetonide, which subsequently cyclises on the alkyne intramolecularly under gold catalysis conditions. This method could be extended to make optically pure bicyclic ketals. Deuterium incorporation experiments were carried out to ascertain the mechanism of the reaction. Sequential activation of epoxide and alkyne moieties by a gold catalyst in acetone as solvent has been achieved. This strategyhas been employed to synthesise bicyclic ketals from epoxy alkynes. Copyright
- Balamurugan, Rengarajan,Kothapalli, Raveendra Babu,Thota, Ganesh Kumar
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supporting information; scheme or table
p. 1557 - 1569
(2011/04/25)
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- Highly E-selective solvent-free Horner-Wadsworth-Emmons reaction catalyzed by DBU
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The solvent-free Horner-Wadsworth-Emmons reaction of triethyl phosphonoacetate with a variety of aldehydes was catalyzed by DBU in the presence of K2CO3 to give E-α,β-unsaturated esters highly selectively (99:1 for most of the reactions). The reaction with ketones gave trisubstituted olefins with good to high E-selectivity by DBU-Cs2CO3.
- Ando, Kaori,Yamada, Kyohei
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supporting information; experimental part
p. 1143 - 1146
(2011/06/24)
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- HETEROCYCLIC DERIVATIVE HAVING INHIBITORY ACTIVITY ON TYPE-I 11 -HYDROXYSTEROID DEHYDROGENASE
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Disclosed is a compound which is useful as an 11β-hydroxysteroid dehydrogenase type 1 inhibitor. A compound represented by the formula: its pharmaceutically acceptable salt, or a solvate thereof, wherein X is O or S, a broken line and a wavy line represent the presence or the absence of a bond, (i) when a broken line represents the presence of a bond, a wavy line represents the absence of a bond, R2 and R3 are each independently hydrogen, halogen, cyano, hydroxy, carboxy, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl or the like, (ii) when a broken line represents the absence of a bond, a wavy line represents the presence of a bond, R1 and R4 are each independently hydrogen, halogen or the like, R2 and R3 are each independently hydrogen, halogen, cyano, hydroxy, carboxy, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl or the like, and R5 and R6 are each independently hydrogen, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl or the like.
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Page/Page column 172
(2010/08/07)
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- P[N(i-Bu)CH2CH2]3N: Nonionic Lewis base for promoting the room-temperature synthesis of α,β-unsaturated esters, fluorides, ketones, and nitriles using Wadsworth - Emmons phosphonates
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The bicyclic triaminophosphine P(RNCH2CH2) 3N (R = i-Bu, 1c) serves as an effective promoter for the room-temperature stereoselective synthesis of α,β-unsaturated esters, fluorides, and nitriles from a wide array of aromatic, aliphatic, heterocyclic, and cyclic aldehydes and ketones, using a range of Wadsworth-Emmons (WE) phosphonates. Among the analogues of 1c [R = Me (1a), i-Pr (1b), Bn (1d)], 1a and 1b performed well, although longer reaction times were involved, and 1d led to poorer yields than 1c. Functionalities such as cyano, chloro, bromo, methoxy, amino, ester, and nitro were well tolerated. We were able to isolate and characterize (by X-ray means; see above) the reactive WE intermediate species formed from 2b and 1c.
- Chintareddy, Venkat Reddy,Ellern, Arkady,Verkade, John G.
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supporting information; experimental part
p. 7166 - 7174
(2010/12/25)
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- Solvent-free Horner-Wadsworth-Emmons reaction using DBU
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The solvent-free Horner-Wadsworth-Emmons reaction with a variety of aldehydes using 1.5 equiv of DBU gave E-α,β-unsaturated esters and ketones in high yields. The E-selectivity was high and the used DBU was recovered.
- Ando, Kaori,Yamada, Kyohei
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experimental part
p. 3297 - 3299
(2010/07/18)
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- A convenient method for the lewis base-catalyzed synthesis of α,β-unsaturated carboxylic esters using trimethylsilylketene ethyl trimethylsilyl acetal and carbonyl compounds
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A highly useful method for the synthesis of α,β-unsaturated carboxylic esters from various carbonyl compounds that uses trimethylsilylbetene ethyl trimethylsilyl acetal in the presence of a Lewis base catalyst such as acetate salts was established. This procedure gives the corresponding esters in high yields with excellent E stereoselectivity under mild conditions. Copyright
- Michida, Makoto,Mukaiyama, Teruaki
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p. 704 - 705
(2008/12/21)
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- Synthesis and biological activity of permethrinic acid analogs containing various substituents in position 2 of the cyclopropane ring
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A number of permethrinic acid ethyl ester derivatives having various substituents [Et, Pr, Ph, Ph(CH2) n (n = 1, 2), etc.] in position 2 of the cyclopropane ring were synthesized, and their insecticidal acivity against typhoid flies, rice weevils, and bean aphides, as well as juvenoid activity on flour beetle chrysalises, was studied. The newly synthesized compounds turned out to exhibit weak insecticidal activity against standard insects but pronounced juvenile hormone activity, which differentiates them from permethrinic acid esters.
- Mirzabekova,Kuz'mina,Lukashov,Sokolova,Golosov,Kazakov,Perlova,Potapova,Kheinman,Ivanova
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experimental part
p. 1139 - 1149
(2009/09/25)
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- An RCM based approach to (±)-herbertene-l, 14-diol and (±)-tochuinyl acetates
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A sequence comprising of Johnson's ortho ester Claisen rearrangement, alkylation and RCM reactions has been developed for the synthesis of cyclopentenes containing vicinal quaternary carbon atoms. The versatility of the sequence has been demonstrated by the efficient total synthesis of sesquiterpenes tochuinyl acetates and herbertene-1,14-diol.
- Srikrishna,Rao, M Sreenivasa
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p. 1308 - 1317
(2008/09/18)
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- The role of achiral pyrazolidinone templates in enantioselective Diels-Alder reactions: Scope, limitations, and conformational insights
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We have evaluated the role of achiral pyrazolidinone templates in conjunction with chiral Lewis acids in room temperature, enantioselective Diels-Alder cycloadditions. The role of the fluxional N(1) substituent was examined, with the bulky 1-naphthylmethyl group providing enantioselectivities up to 99% ee, while templates with smaller fluxional groups gave lower selectivities. High selectivities were also observed in reactions of 7d with chiral Lewis acids derived from relatively small chiral ligands, suggesting the pyrazolidinone templates are capable of relaying stereochemical information from the ligand to the reaction center. Lewis acids capable of adapting square planar geometries, such as Cu(OTf)2, Cu(ClO4)2, and Pd(ClO4)2, were found to be particularly effective at providing high selectivities. Additionally, substitution at the C-5 position of the pyrazolidinone templates has been shown to be critical for optimal selectivity. Reactions of the optimal pyrazolidinone appended with a number of common dienophiles and various dienes demonstrate the utility of this achiral template. Furthermore, catalytic loadings could be lowered to 2.5 mol % with essentially no loss in selectivity, π-π interactions were evaluated as a means to explain the unusually high selectivity observed at room temperature. Finally, non-C2-symmetric ligands were employed as a test to determine if chiral relay was operative.
- Sibi, Mukund P.,Stanley, Levi M.,Nie, Xiaoping,Venkatraman, Lakshmanan,Liu, Mei,Jasperse, Craig P.
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p. 395 - 405
(2007/10/03)
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- Microwave-assisted regioselective olefinations of cyclic mono- and di-ketones with a stabilized phosphorus ylide
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A number of cyclic mono- and di-ketones underwent regioselective olefination with (carbethoxyethylidene)triphenylphospharane under controlled microwave heating. The Wittig reaction of 4-substituted cyclohexanones or 1,2- and 1,4-cyclohexanediones with the ylide at 190 °C for 20 min in MeCN afforded the exocyclic olefins in >94:6 isomer ratios. On the other hand, the same reactions carried out at 230 °C for 20 min in the presence of 20 mol % DBU furnished the endocyclic olefins in >83:17 isomer ratios. The base-mediated isomerization of the exocyclic olefins into the endocyclic isomers was primarily driven by thermodynamic stability of the products and the effect of ring structures on deconjugation was examined.
- Wu, Jinlong,Li, Dan,Wu, Huafeng,Sun, Lijie,Dai, Wei-Min
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p. 4643 - 4650
(2007/10/03)
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- Umpolung of Michael acceptors catalyzed by N-heterocyclic carbenes
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N-Heterocyclic carbenes can catalyze β-alkylations of a range of α,β-unsaturated esters, amides, and nitriles that bear pendant leaving groups to form a variety of ring sizes. In this process, the nucleophilic catalyst transiently transforms the normally electrophilic β carbon into a nucleophilic site through an unanticipated addition-tautomerization sequence. Copyright
- Fischer, Christian,Smith, Sean W.,Powell, David A.,Fu, Gregory C.
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p. 1472 - 1473
(2007/10/03)
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- INHIBITORS OF PHOSPHODIESTERASE TYPE-IV
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The present invention relates to isoxazoline derivatives, which can be used as selective inhibitors of phosphodiesterase (PDE) type IV. In particular, compounds disclosed herein can be useful in the treatment of AIDS, asthma, arthritis, bronchitis, chronic obstructive pulmonary disease (COPD), psoriasis, allergic rhinitis, shock, atopic dermatitis, Crohn's disease, adult respiratory distress syndrome (ARDS), eosinophilic granuloma, allergic conjunctivitis, osteoarthritis, ulcerative colitis and other inflammatory diseases in a patient, particularly in humans. The present invention also relates to processes for the preparation of disclosed compounds, as well as pharmaceutical compositions thereof, and their use as phosphodiesterase (PDE) type IV inhibitors.
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Page/Page column 41-42
(2008/06/13)
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- Catalytic ketone olefination with methyltrioxorhenium
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Methyltrioxorhenium (MTO) catalyses the olefination of ketones with ethyl diazoacetate in the presence of triphenylphosphane. Unactivated ketones require the addition of 0.5 equiv of benzoic acid to achieve good yields, while trifluoromethyl ketones require no co-catalyst. The optimised system allows the olefination of aromatic, aliphatic, unsaturated, cyclic and trifluoromethyl ketones.
- Pedro, Filipe M.,Hirner, Sebastian,Kühn, Fritz E.
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p. 7777 - 7779
(2007/10/03)
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- Ligand-accelerated vanadium-catalysed epoxidation in water
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Vanadium-catalysed epoxidation of allylic alcohols, a classical example of ligand-decelerated catalysis, in water it turns into a ligand-accelerated process. The Royal Society of Chemistry 2005.
- Bourhani, Zainaba,Malkov, Andrei V.
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p. 4592 - 4594
(2007/10/03)
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- New application of bromotrimethylsilane: Elaboration of aldehydes/ketones into homologous α,β-unsaturated esters via β-hydroxy esters
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α,β-Unsaturated esters are formed when β-hydroxy esters react with bromotrimethylsilane which is generated from chlorotrimethylsilane- lithium bromide in acetonitrile. Copyright Taylor & Francis, Inc.
- Suri, Suresh C.,Marcischak, Jacob C.
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p. 379 - 387
(2007/10/03)
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- Fluoro-olefins as peptidomimetic inhibitors of dipeptidyl peptidases
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The feasibility of the fluoro-olefin function as a peptidomimetic group in inhibitors for dipeptidyl peptidase IV and II (DPP IV and DPP II) is investigated by evaluation of N-substituted Gly-Ψ[CF=C]pyrrolidines, Gly-Ψ[CF=C]piperidines, and Gly-Ψ[CF=C](2-cyano)pyrrolidines. Of this later class, the (Z)- and (E)-fluoro-olefin analogues were prepared and chemical stability in comparison with the parent amide was checked. Most of these compounds exhibited a strong binding preference toward DPP II with IC 50 values in the low micromolar range, while only low DPP IV inhibitory potential is seen.
- Van Der Veken, Pieter,Senten, Kristel,Kertèsz, István,De Meester, Ingrid,Lambeir, Anne-Marie,Maes, Marie-Berthe,Scharpé, Simon,Haemers, Achiel,Augustyns, Koen
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p. 1768 - 1780
(2007/10/03)
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- Discovery and preclinical profile of saxagliptin (BMS-477118): A highly potent, long-acting, orally active dipeptidyl peptidase IV inhibitor for the treatment of type 2 diabetes
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Efforts to further elucidate structure-activity relationships (SAR) within our previously disclosed series of β-quaternary amino acid linked L-cis-4,5-methanoprolinenitrile dipeptidyl peptidase IV (DPP-IV) inhibitors led to the investigation of vinyl substitution at the β-position of α-cycloalkyl-substituted glycines. Despite poor systemic exposure, vinyl-substituted compounds showed extended duration of action in acute rat ex vivo plasma DPP-IV inhibition models. Oxygenated putative metabolites were prepared and were shown to exhibit the potency and extended duration of action of their precursors in efficacy models measuring glucose clearance in Zuckerfa/fa rats. Extension of this approach to adamantylglycine- derived inhibitors led to the discovery of highly potent inhibitors, including hydroxyadamantyl compound BMS-477118 (saxagliptin), a highly efficacious, stable, and long-acting DPP-IV inhibitor, which is currently undergoing clinical trials for treatment of type 2 diabetes.
- Augeri, David J.,Robl, Jeffrey A.,Betebenner, David A.,Magnin, David R.,Khanna, Ashish,Robertson, James G.,Wang, Aiying,Simpkins, Ligaya M.,Taunk, Prakash,Huang, Qi,Han, Song-Ping,Abboa-Offei, Benoni,Cap, Michael,Xin, Li,Tao, Li,Tozzo, Effie,Welzel, Gustav E.,Egan, Donald M.,Marcinkeviciene, Jovita,Chang, Shu Y.,Biller, Scott A.,Kirby, Mark S.,Parker, Rex A.,Hamann, Lawrence G.
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p. 5025 - 5037
(2007/10/03)
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