- Tilting a ground-state reactivity landscape by vibrational strong coupling
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Many chemical methods have been developed to favor a particular product in transformations of compounds that have two or more reactive sites. We explored a different approach to site selectivity using vibrational strong coupling (VSC) between a reactant and the vacuum field of a microfluidic optical cavity. Specifically, we studied the reactivity of a compound bearing two possible silyl bond cleavage sites—Si–C and Si–O, respectively—as a function of VSC of three distinct vibrational modes in the dark. The results show that VSC can indeed tilt the reactivity landscape to favor one product over the other. Thermodynamic parameters reveal the presence of a large activation barrier and substantial changes to the activation entropy, confirming the modified chemical landscape under strong coupling.
- Thomas, A.,Lethuillier-Karl, L.,Nagarajan, K.,Vergauwe, R. M. A.,George, J.,Chervy, T.,Devaux, E.,Genet, C.,Moran, J.,Ebbesen, T. W.,Shalabney, A.
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Read Online
- An Asymmetric Pathway to Dendrobine by a Transition-Metal-Catalyzed Cascade Process
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An asymmetric pathway to the caged tetracyclic pyrrolidine alkaloid, dendrobine, is reported. The successful synthetic strategy features a one-pot, sequential palladium-catalyzed enyne cycloisomerization and rhodium-catalyzed diene-assisted pyrrolidine formation by allylic CH activation. The developed transition-metal-catalyzed cascade process permits rapid access to the dendrobine core structure and circumvents the handling of labile intermediates. An intramolecular aldol condensation under carefully defined reaction conditions takes place with a concomitant detosylation, followed by reductive amine methylation, to afford a late-stage intermediate (previously identified by several prior dendrobine syntheses) in only 10 synthetic steps overall.
- Lee, Yujin,Rochette, Elise M.,Kim, Junyong,Chen, David Y.-K.
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Read Online
- Total Synthesis of Laingolide B Stereoisomers and Assignment of Absolute Configuration
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Total synthesis of (-)-(2R,9S)- and (+)-(2S,9S)-stereoisomers of laingolide B has been accomplished by using sequential ring-closing metathesis (RCM) and alkene isomerization to construct the macrocyclic trans-N-methyl enamide moiety. The Myers alkylation
- Cui, Chengsen,Dai, Wei-Min
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Read Online
- Synthesis of the oxygenated bicyclo[9.3.1]pentadecane ring system of phomactin A using chromium (II)-mediated macrocyclisation and ring closure metathesis
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Treatment of the aldehyde vinyl iodides 17, 19a and 19b in DMSO with CrCl2-NiCl2 resulted in their macrocyclisation to the oxygenated ring systems 18, 20, and 21 respectively (43-63%) of the PAF antagonist phomactin A isolated from t
- Foote,John,Pattenden
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Read Online
- COMPOSITIONS AND METHODS FOR PARASITE CONTROL
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The present invention relates in its broadest aspect to a compound of Formula I as provided herein, formulations comprising such a compound and corresponding uses thereof for the reduction of infestation with ectoparasites, in particular ectoparasites of the insect class, including fleas and mosquitoes and/or ectoparasites of the arachnid class, including ticks and mites, etc. Also provided herein are methods for preparing the formulations of the invention and methods for controlling ectoparasites using the compounds and/or formulations provided herein.
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Page/Page column 55; 65
(2022/01/05)
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- Synthesis of [6,6,m]-Tricyclic Compounds via [4+2] Cycloaddition with Au or Cu Catalyst
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We synthesized [6,6,6]- and [6,6,7]-tricyclic compounds via intramolecular [4+2] cycloaddition by gold or copper catalysts. Substrates for cyclization were prepared by coupling reactions between eight types of diyne and four types of aromatic moieties. We have successfully synthesized eleven tricyclic compounds.
- Kang, Juyeon,Ham, Seunghwan,Seong, Chaehyeon,Oh, Chang Ho
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supporting information
p. 1039 - 1043
(2021/05/05)
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- Methyl-Shifted Farnesyldiphosphate Derivatives Are Substrates for Sesquiterpene Cyclases
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New sesquiterpene backbones are accessible after biotransformation of presilphiperfolan-8β-ol synthase (BcBOT2), a fungal sesquiterpene synthase, with non-natural farnesyldiphosphates in which methyl groups are shifted by one position toward the diphosphate terminus. One of the macrocycles formed, a new germacrene A derivative, undergoes a Cope rearrangement to iso-β-elemene. Three of the new terpenoids show olfactoric properties that range from an intense peppery note to a citrus, ozone-like, and fruity scent.
- Harms, Vanessa,Schr?der, Benjamin,Oberhauser, Clara,Tran, Cong Duc,Winkler, Sven,Dr?ger, Gerald,Kirschning, Andreas
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supporting information
p. 4360 - 4365
(2020/06/08)
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- Total Synthesis of Kalimantacin A
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The kalimantacins make up a family of hybrid polyketide-nonribosomal peptide-derived natural products that display potent and selective antibiotic activity against multidrug resistant strains of Staphylococcus aureus. Herein, we report the first total synthesis of kalimantacin A, in which three fragments are prepared and then united via Sonogashira and amide couplings. The enantioselective synthetic approach is convergent, unlocking routes to further kalimantacins and analogues for structure-activity relationship studies and clinical evaluation.
- Davies, Jonathan A.,Bull, Freya M.,Walker, Paul D.,Weir, Angus N. M.,Lavigne, Rob,Masschelein, Joleen,Simpson, Thomas J.,Race, Paul R.,Crump, Matthew P.,Willis, Christine L.
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supporting information
p. 6349 - 6353
(2020/09/02)
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- Total Synthesis of 1-Oxomiltirone and Arucadiol
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A practical and efficient approach for the total synthesis of arucadiol and 1-oxomiltirone is reported. The key step which involves an intramolecular [4+2] cycloaddition catalyzed by gold(III) bromide or copper(II) triflate leads to the formation of 6-6-6-fused aromatic abietane core.
- Chai, Uiseong,Kang, Juyeon,Mac, Dinh Hung,Oh, Chang Ho,Seong, Chaehyeon
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supporting information
p. 1953 - 1956
(2020/11/24)
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- Construction of sequence-defined polytriazoles by IrAAC and CuAAC reactions
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Here we report the first synthesis of sequence-defined polytriazoles, in which different side groups are sequentially anchored to the C-5 position of 1,2,3-triazole rings. By using efficient synthetic strategies based on IrAAC and CuAAC, different monodis
- Ding, Shengtao,Ju, Changhong,Ma, Jiahao,Meng, Congcong,Zhang, Xueyan
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supporting information
p. 3955 - 3958
(2020/04/17)
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- Sulfones as Synthetic Linchpins: Transition-Metal-Free sp3–sp2 and sp2–sp2 Cross-Couplings Between Geminal Bis(sulfones) and Organolithium Compounds
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A valuable umpolung strategy that highlights the ambiphilic nature of the bis(phenylsulfonyl)methyl synthon and demonstrates its utility as a synthetic linchpin is reported. Although the bis(phenylsulfonyl)methyl group is typically introduced as an sp3-carbon nucleophile, it is demonstrated that it can also function as an effective sp2-carbon electrophile in the presence of organolithium nucleophiles. Alkyl- and aryllithiums couple with the central carbon of the bis(phenylsulfonyl)methyl unit to ultimately generate trisubstituted alkenes, comprising formal sp3–sp2 and sp2–sp2 cross-couplings between organolithium reagents and bis(sulfones). This process occurs almost instantaneously at ?78 °C in the absence of any transition metals. By developing this curious transformation, it has been demonstrated that bis(phenylsulfonyl)methane is a valuable synthetic linchpin, which can undergo two C?C bond-forming processes as an sp3-nucleophile, followed by a third C?C bond-forming reaction as an effective sp2-electrophile. This discovery significantly enhances the utility of this ubiquitous, but underutilized, linker group.
- Trost, Barry M.,Kalnmals, Christopher A.
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supporting information
p. 9066 - 9074
(2018/06/29)
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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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supporting information
p. 739 - 743
(2013/02/23)
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- Silver-catalysed intramolecular hydroamination of alkynes with trichloroacetimidates
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Silver(i) complexes catalyse the intramolecular addition of trichloroacetimidates to alkynes. In the absence of a ligand, the selectivity of the reaction is dependent upon the nature of the counter-anion and solvent. The introduction of non-chelating nitrogeneous ligands suppresses competitive Bronsted acid catalysis, improving the yield and selectivity of the reaction.
- Wong, Valerie H. L.,Hor, T. S. Andy,Hii, King Kuok
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supporting information
p. 9272 - 9274
(2013/10/01)
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- PYRAZOLOPYRIMIDINES, A PROCESS FOR THEIR PREPARATION AND THEIR USE AS MEDICINE
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The invention relates to pyrazolopyrimidine derivatives as well as their pharmaceutically acceptable salts. The invention further relates to a process for the preparation of such compounds. The compounds of the invention are mGluR5 modulators and are ther
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Page/Page column 74
(2010/06/20)
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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 pyridines and pyrazines using an intramolecular hydroamination-based reaction sequence
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A management issue! Various pyridines and pyrazines can be efficiently accessed from simple acyclic precursors using an intramolecular hydroamination/isomerization/aromatization sequence (see scheme). ρ-Toluenesulfonic acid (2 mol%) is used to catalyze this novel alkyne annulation, in which the oxime group allows for a subsequent redoxneutral aromatization step to occur.
- Rizk, Toni,Bilodeau, Eric J.-F.,Beauchemin, Andre M.
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supporting information; experimental part
p. 8325 - 8327
(2010/01/16)
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- Copper-catalyzed asymmetric conjugate addition with chiral SimplePhos ligands
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SimplePhos ligands represent a novel class of monodentate chiral ligands based on a chiral amine moiety and flexible diaryl groups on the phosphorous atom. They can be easily prepared by two different pathways and they can be highly functionalised. Herein we report the copper-catalysed asymmetric conjugate addition of diethyl zinc and trialkylaluminium reagents with SimplePhos ligands, which gives high enantioselectivity with cyclic enones, acyclic enones and nitro-olefins, with up to 98.6 % ee. Of particular interest is the reaction of trialkylaluminium reagents with a wide range of 3substituted enones, thus allowing the formation of stereogenic quaternary carbon centres.
- Palais, Laetitia,Alexakis, Alexandre
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supporting information; experimental part
p. 10473 - 10485
(2010/05/02)
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- Direct coupling of alcohols with alkenylsilanes catalyzed by indium trichloride or bismuth tribromide
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Indium halides or bismuth halides catalyzed the coupling of various alcohols with alkenylsilanes to give the corresponding alkenes stereospecifically without any other activators. The Royal Society of Chemistry 2008.
- Nishimoto, Yoshihiro,Kajioka, Masayuki,Saito, Takahiro,Yasuda, Makoto,Baba, Akio
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supporting information; experimental part
p. 6396 - 6398
(2009/04/13)
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- Asymmetric synthesis of enantioenriched (+)-elaeokanine A
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The key transformation in the total synthesis of (+)-elaeokanine A was accomplished by asymmetric deprotonation of N-Boc pyrrolidine, followed by the reaction of the in situ generated enantioenriched stereogenic cuprate reagent with (E)-4-bromo-l-iodo-l-trimethylsilyl-l-butene with retention of configuration. N-Boc deprotection, followed by a one-pot olefin isomerization and intramolecular amine alkylation afforded a bicyclic vinyl bromide that was converted into (+)-elaeokanine A by sequential halogen metal exchange and reaction of the organolithium reagent with N-butanoylmorpholine.
- Dieter, R. Karl,Chen, Ningyi
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p. 5674 - 5678
(2007/10/03)
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- Trimethylaluminum (TMA)-catalyzed reaction of alkynyllithiums with ethylene oxide: Increased yields and purity of homopropargylic alcohols
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An efficient protocol was developed to obtain homopropargylic alcohols. Subjecting alkynyllithiums and ethylene oxide to 10-20 mol% of trimethylaluminum provided homopropargylic alcohols in good yields. Georg Thieme Verlag Stuttgart.
- Brummond, Kay M.,McCabe, Jamie M.
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p. 2457 - 2460
(2007/10/03)
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- The aza-silyl-Prins reaction: A novel method for the synthesis of trans-2,6-tetrahydropyridines
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Reaction of 4-trimethylsilyl-3-butenyl-1-amines with aldehydes under mild Lewis acid conditions gives substituted tetrahydropyridines in excellent yields and with excellent trans diastereoselectivity.
- Dobbs, Adrian P.,Guesné, Sebastien J. J.,Hursthouse, Michael B.,Coles, Simon J.
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p. 1740 - 1742
(2007/10/03)
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- Synthetic studies towards the phomactins. Concise syntheses of the tricyclic furanochroman and the oxygenated bicyclo[9.3.1]pentadecane ring systems in phomactin A.
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A concise synthesis of the tricyclic furanochroman unit 3 found in the PAF antagonist phomactin A (1) isolated from the marine fungus Phoma sp., is described. In complementary studies, a variety of synthetic routes towards the bicyclo[9.3.1]pentadecane ring system 4 in phomactin A were explored. These studies culminated in a synthesis of the substituted ring system 79 containing all the carbon atoms and all the necessary oxygen centres for elaboration to phomactin A itself.
- Foote, Kevin M,Hayes, Christopher J,John, Matthew P,Pattenden, Gerald
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p. 3917 - 3948
(2007/10/03)
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- Stereoselective Synthesis and Binding Properties of Novel Concave-Shaped Indolizmo[3,4-b]quinolines
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Novel all-cis-configurated indolizino[3,4-b]quinoline receptors 3,4 were prepared via diastereoselective Lewis acid-catalyzed cyclization of N-arylimines 6,7 as the key step. In order to obtain the indolizino[3,4-b]quinoline derivative 21 without a gem-di
- Dickner, Tim,Laschat, Sabine
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p. 804 - 811
(2007/10/03)
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- Heteroaryl radicals in synthesis: Radical cyclisation reactions of 2-bromoindoles
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The synthesis and radical cyclisations of 2-bromoindoles carrying an unsaturated N-alkyl group is described.
- Dobbs, Adrian P.,Jones, Keith,Veal, Ken T.
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p. 2149 - 2160
(2007/10/03)
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- O→Csp Migration of the Trimethylsilyl Group in Alkynyl Trimethylsilyl Ethers
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1,4- and 1,5-O→Csp-Migration of the trimethylsilyl group in Grignard derivatives of α- and β-acetylenic trimethylsilyl ethers, followed by hydrolysis, results in formation of trimethylsilylalkynyl alcohols. The reactivity of alkynyl trimethylsilyl ethers in the isomerization is determined by the structure of the substrate and reaction conditions (polarity of the medium and concentration of the reactants).
- Novokshonov,Medvedeva,Demina,Sherstyannikova,Voronkov
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p. 1770 - 1773
(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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- Synthesis of the 5-HT1D receptor agonist MK-0462 via a Pd-catalyzed coupling reaction
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Application of a palladium-catalyzed coupling between 3 and 5a to the synthesis of the novel 5-HT1D receptor agonist MK-0462 (1), a potential anti-migraine drug, is described.
- Chen, Cheng-Yi,Lieberman, David R.,Larsen, Robert D.,Reamer, Robert A.,Verhoeven, Thomas R.,Reider, Paul J.,Cottrell, Ian F.,Houghton, Peter G.
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p. 6981 - 6984
(2007/10/02)
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- A Novel and Stereodefined Synthesis of (E)-β-Ethoxycarbonylvinylsilanes: Regio- and Stereo-controlled Hydroethoxycarbonylation of Silylacetylenes by Palladium(II) Catalysis
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-SnCl2*2H2O catalysed hydroethoxycarbonylation of silylacetylenes 1 provided a novel and convenient synthesis of (E)-β-ethoxycarbonylvinylsilanes 2.The reactions, carried out under mild conditions (90 deg C, 20 kg cm-2) gave the pr
- Takeuchi, Ryo,Sugiura, Masaharu
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p. 1031 - 1038
(2007/10/02)
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- Tetrahydropyridine oxime compounds
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Certain N-substituted 1-(1,2,3,6-tetrahydro-3-pyridinyl)oximes and N-substituted 1-(1,2,3,6-tetrahydro-4-pyridinyl)oximes are useful as sigma binding agents for the treatment of depression, psychoses and/or inflammatory diseases.
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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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- Total Synthesis of (+/-)-Δ9(12)-Capnellene-8β,10α-diol
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A total synthesis of (+/-)-Δ9(12)-capnellene-8β,10α-diol (1), containing a cis,anti,cis-tricyclo2,6>undecane carbon framework, found in the marine coral Capnella imbricata, is described.Michael addition of the homo-allylic cuprate (21) to 3-methylcyclopentenone, followed by Lewis acid catalysed 'ene-type' cyclisation of the resulting specific enol ester (22), first provided an expeditious route to the central bicyclooctanone intermediate (24).Alkylation of the enolate derived from (24) with 2-chloro-4-iodobut-2-ene (28) then produced compound (29), which was converted into the keto-acetylene (32) using the acetylene 'zipper' methodology.When compound (32) was titrated with sodium naphthalene radical anion smooth reductive cyclisation occured producing the tricyclic allylic alcohol (33).Oxidation of compound (33) with catalytic selenium dioxide then led to the 8-epi-capnellenediol (34).Finally, displacement of the methanesulphonate derived from (34), with potassium superoxide in 18-crown-6, produced (+/-)-Δ9(12)-capnellene-8β,10α-diol (1), which showed 1H- and 13C-n.m.r. spectra in addition to m.s. data identical with naturally derived material.
- Pattenden, Gerald,Teague, Simon J.
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p. 1077 - 1084
(2007/10/02)
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- 2-Substituted prostaglandins
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The present invention encompasses 16-alkyl, 16-hydroxy-2-substituted prostaglandins which exhibit cytoprotective and antisecretory activity with greatly reduced diarrhea side effects.
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- Silicon in Synthesis. 21. Reagents for Thiophenyl-Functionalized Cyclopentenone Annulations and the Total Synthesis of (+/-)-Hirsutene
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1-(Trimethylsilyl)-1-(phenylthio)ethylene (1) reacts with cyclic α,β-unsaturated acid chlorides to give β-mercaptophenyl-substituted cyclopentenones, whereas 1-(trimethylsilyl)-2-(phenylthio)ethylene (2) under similar conditions results in thiophenyl migr
- Magnus, Philip,Quagliato, Dominick
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p. 1621 - 1626
(2007/10/02)
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- REACTION OF PROPARGYL BROMIDE AND TRIMETHYLSILYLPROPARGYL IODIDE WITH METALLIC TIN, ALUMINIUM, AND ALDEHYDES OR KETONES. SELECTIVE SYNTHESIS OF β-ACETYLENE, β-TRIMETHYLSILYLACETYLENE, AND α-TRIMETHYLSILYLALLENE ALCOHOLS
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β-Acetylenic and α-allenic alcohols were synthesized selectively by the reaction of aldehydes and ketones with organotin compounds prepared by treatment of propargyl bromide or trimethylsilylpropargyl iodide with metallic tin and aluminium in a suitable solvent.
- Nokami, Junzo,Tamaoka, Takashi,Koguchi, Tadao,Okawara, Rokuro
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p. 1939 - 1942
(2007/10/02)
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