- Organocatalytic Access to a cis-Cyclopentyl-γ-amino Acid: An Intriguing Model of Selectivity and Formation of a Stable 10/12-Helix from the Corresponding γ/α-Peptide
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In this study, we have developed a highly enantioselective organocatalytic route to the (1S,2R)-2-(aminomethyl)cyclopentane-1-carboxylic acid monomer precursor, which has a cis-configuration between the C- and N-termini around the cyclopentane core. Kinet
- Fanelli, Rossana,Berta, Dénes,F?ldes, Tamás,Rosta, Edina,Atkinson, Robert Andrew,Hofmann, Hans-J?rg,Shankland, Kenneth,Cobb, Alexander J. A.
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supporting information
p. 1382 - 1393
(2020/01/09)
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- Macrocyclic Modulators of the Ghrelin Receptor
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The present invention provides novel conformationally-defined macrocyclic compounds that have been demonstrated to be selective modulators of the ghrelin receptor (growth hormone secretagogue receptor, GHS-R1a and subtypes, isoforms and variants thereof). Methods of synthesizing the novel compounds are also described herein. These compounds are useful as agonists of the ghrelin receptor and as medicaments for treatment and prevention of a range of medical conditions including, but not limited to, metabolic and/or endocrine disorders, gastrointestinal disorders, cardiovascular disorders, obesity and obesity-associated disorders, central nervous system disorders, genetic disorders, hyperproliferative disorders and inflammatory disorders.
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Paragraph 0429; 0431
(2018/05/03)
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- Simple, copper(I)-catalyzed oxidation of benzylic/allylic alcohols to carbonyl compounds: Synthesis of functionalized cinnamates in one pot
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An environmentally benign [Cu(I)]-catalyzed oxidation of activated (benzylic/allylic) alcohols to the corresponding carbonyl compounds is presented. Interestingly, the reaction was also compatible with benzylic alcohols containing ortho-bromo substituents on the aromatic ring without competing with the expected intermolecular Buchwald coupling. Significantly, the catalytic system enables the synthesis of cinnamate-esters in a sequential domino one-pot fashion via oxidation followed by Wittig-Horner protocol. Copyright
- Reddy, Alavala Gopi Krishna,Mahendar, Lodi,Satyanarayana, Gedu
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supporting information
p. 2076 - 2087
(2014/07/07)
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- Organocatalytic, enantioselective intramolecular [6 + 2] cycloaddition reaction for the formation of tricyclopentanoids and insight on its mechanism from a computational study
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Diphenylprolinol silyl ether was found to be an effective organocatalyst for promoting the asymmetric, catalytic, intramolecular [6 + 2] cycloaddition reactions of fulvenes substituted at the exocyclic 6-position with a δ-formylalkyl group to afford synthetically useful linear triquinane derivatives in good yields and excellent enantioselectivities. The cis-fused triquinane derivatives were obtained exclusively; the trans-fused isomers were not detected among the reaction products. The intramolecular [6 + 2] cycloaddition occurs between the fulvene functionality (6π) and the enamine double bond (2π) generated from the formyl group in the substrates and the diphenylprolinol silyl ether. The absolute configuration of the reaction products was determined by vibrational circular dichroism. The reaction mechanism was investigated using molecular orbital calculations, B3LYP and MP2 geometry optimizations, and subsequent single-point energy evaluations on model reaction sequences. These calculations revealed the following: (i) The intermolecular [6 + 2] cycloaddition of a fulvene and an enamine double bond proceeds in a stepwise mechanism via a zwitterionic intermediate. (ii) On the other hand, the intramolecular [6 + 2] cycloaddition leading to the cis-fused triquinane skeleton proceeds in a concerted mechanism via a highly asynchronous transition state. (iii) The fulvene functionality and the enamine double bond adopt the gauche-syn conformation during the C-C bond formation processes in the [6 + 2] cycloaddition. (iv) The energy profiles calculated for the intramolecular reaction explain the observed exclusive formation of the cis-fused triquinane derivatives in the [6 + 2] cycloaddition reactions. The reasons for the enantioselectivity seen in these [6 + 2] cycloaddition reactions are also discussed.
- Hayashi, Yujiro,Gotoh, Hiroaki,Honma, Masakazu,Sankar, Kuppusamy,Kumar, Indresh,Ishikawa, Hayato,Konno, Kohzo,Yui, Hiroharu,Tsuzuki, Seiji,Uchimaru, Tadafumi
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supporting information; experimental part
p. 20175 - 20185
(2012/01/31)
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- Discovery of a new class of macrocyclic antagonists to the human motilin receptor
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A novel class of macrocyclic peptidomimetics was identified and optimized as potent antagonists to the human motilin receptor (hMOT-R). Well-defined structure-activity relationships allowed for rapid optimization of potency that eventually led to high aff
- Marsault, Eric,Hoveyda, Hamid R.,Peterson, Mark L.,Saint-Louis, Carl,Landry, Annick,Vézina, Martin,Quellet, Luc,Wang, Zhigang,Ramaseshan, Mahesh,Beaubien, Sylvie,Benakli, Kamel,Beauchemin, Sophie,Déziel, Robert,Peeters, Théo,Fraser, Graeme L.
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p. 7190 - 7197
(2007/10/03)
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- Highly diastereoselective radical cyclizations on soluble ring opening metathesis supports
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equation presented This study represents the first examples of stereoselective radical cyclizations on soluble supports. A stereocontrol element consisting of a polymer-imbedded (+)-isosorbide chiral auxiliary was used in each monomer subunit. A survey of
- Enholm, Eric J.,Cottone, Jennifer S.
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p. 3959 - 3960
(2007/10/03)
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- Neighboring assistance of a hydroxyl group on manganese dioxide oxidation of benzyl alcohols to lactones
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o-Hydroxymethylbenzyl alcohol and o-hydroxyethylbenzyl alcohols have been converted to phthalide and dihydroisocoumarins, very easily and in high yields, by oxidation with non-activated manganese dioxide. In contrast, the reaction of o-hydroxypropylbenzyl alcohol stopped at the aldehyde level, and afforded only a small amount of the corresponding lactone under the same condition. This implies that the first oxidation product, a benzaldehyde, could be oxidized further via a hemiacetal, but the second oxidation to lactone is very much dependent on the ability of stable intramolecular hemiacetal formation, and not on the intermolecular mode at all.
- Endo, Katsuya,Takahashi, Hiroyasu,Aihara, Minako
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p. 589 - 615
(2007/10/03)
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- Synthesis of New Five-Atom-Linked Capped Porphyrins
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The synthesis and characterization of three new five-atom-linked "capped" porphyrins, 6, 12, and 18, are reported.The general synthetic procedure involves synthesis of a tetraaldehyde "cap" by reacting the five-atom "arm" with 1,2,4,5-tetrahydroxybenzene
- Ma, Wuping,Slebodnick, Carla,Ibers, James A.
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p. 6349 - 6353
(2007/10/02)
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- Radical isomerization via intramolecular ipso substitution of aryl ethers: Aryl translocation from oxygen to carbon
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Bromopropyl aryl ethers an converted to 3-arylpropanols under standard radical generating conditions in the presence of tributylstannane and AIBN. This rearrangement involves intramolecular ipso attack of the alkyl radicals which generates spiro cyclohexadienyl radical intermediates.
- Lee, Eun,Lee, Chulbom,Tae, Jin Sung,Whang, Ho Sung,Li, Kap Sok
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p. 2343 - 2346
(2007/10/02)
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