- Ir-Catalyzed Remote Functionalization by the Combination of Deconjugative Chain-Walking and C-H Activation Using a Transient Directing Group
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An Ir-catalyzed reaction of N-benzylideneanilines with functionalized alkenes such as α,β-unsaturated esters gave ortho-substituted benzaldehyde derivatives with a functional group at the remote position after acidic treatment. The present transformation
- Tang, King Hung Nigel,Uchida, Kanako,Nishihara, Kazuki,Ito, Mamoru,Shibata, Takanori
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supporting information
p. 1313 - 1317
(2022/02/23)
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- Transition Metal-Free Reduction of Activated Alkenes Using a Living Microorganism
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Microorganisms can be programmed to perform chemical synthesis via metabolic engineering. However, despite an increasing interest in the use of de novo metabolic pathways and designer whole-cells for small molecule synthesis, the inherent synthetic capabilities of native microorganisms remain underexplored. Herein, we report the use of unmodified E. coli BL21(DE3) cells for the reduction of keto-acrylic compounds and apply this whole-cell biotransformation to the synthesis of aminolevulinic acid from a lignin-derived feedstock. The reduction reaction is rapid, chemo-, and enantioselective, occurs under mild conditions (37 °C, aqueous media), and requires no toxic transition metals or external reductants. This study demonstrates the remarkable promiscuity of central metabolism in bacterial cells and how these processes can be leveraged for synthetic chemistry without the need for genetic manipulation.
- Brewster, Richard C.,Suitor, Jack T.,Bennett, Adam W.,Wallace, Stephen
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supporting information
p. 12409 - 12414
(2019/08/16)
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- Synthesis of orthogonally protected (2S)-2-amino-adipic acid (α-AAA) and (2S,4 R)-2-amino-4-hydroxyadipic acid (Ahad)
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(2S,4R)-2-Amino-4-hydroxyadipic acid (Ahad) building block 45 was synthesized in 11 steps and 6.5% overall yield from commercially available materials. Key steps in stereocontrol were an asymmetric conjugate addition employing a proline-based catalyst and a syn-selective intramolecular-conjugate addition of an oxygen nucleophile to an α,β-unsaturated ester. To enable incorporation of α-amino-adipic acid (α-AAA) and Ahad into peptides, a truly orthogonal protecting group scheme was developed, encompassing an allyloxycarbonyl (Alloc) carbamate for Nα, a tert-butyl ester for the δ-COOH, an acetol ester for the α-COOH, and a tert- butyldimethylsilyl ether for the γ-hydroxy group of Ahad.
- Yadav, Saroj,Taylor, Carol M.
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p. 5401 - 5409
(2013/07/26)
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- Z-selective intramolecular horner-wadsworthemmons reaction for the synthesis of macrocyclic lactones
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(Figure Presented) When the substrates (ArO)2P(O)CH 2CO2...CHO (Ar = Ph, o-tBuPh) were added to a THF solution containing 3 equiv of NaH at 0 °C or Nal DBU at rt over 1-10 h, the intramolecular Horner-Wadsworth-Emmons reaction proceeded efficiently to give the 12-18-membered-ring lactones in 69-93% yields with 89-100% Z selectivity. On the other hand, (EtO)2P(O)CH2CO2-GHO gave the 13-18-membered-ring lactones in 52-82% yields with 89-99% E selectivity using LiCI-DBU in MeCN or THF.
- Ando, Kaori,Narumiya, Kenji,Takada, Hirokazu,Teruya, Taiji
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scheme or table
p. 1460 - 1463
(2010/06/15)
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- METHOD AND DEVICE
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A method of providing suspended cells (10) for carrying out biological assays, comprising the steps of: a) providing a frozen cell suspension, b) bringing the frozen cell suspension into direct contact with an excess volume of thawing buffer (12), and c) incubating the solution of step b) at room temperature in order to thaw the cell suspension.
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Page/Page column 17-18
(2008/06/13)
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- "Flexiball" toolkit: A modular approach to self-assembling capsules
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We report the synthesis and characterization of new, self-assembling molecular capsules. The modular strategy makes use of glycoluril building blocks available in multigram amounts combined with aromatic spacer elements. The lengthy syntheses encountered with earlier generations of capsules are avoided, and several capsules of nanometer dimensions are now accessible. Single bond attachments between spacers and glycoluril modules result in monomers as dimeric capsules that are less rigid than their earlier counterparts. The host-guest properties of the homo- and heterodimeric capsules were studied using a combination of NMR and ESI-mass spectrometry. They show a less pronounced selectivity for guests of different sizes, and their increased flexibility prevents self-assembly when no rigidifying elements are present on the central spacer unit. Some of the new capsules bear inwardly directed, secondary amide N-H protons. These can be further functionalized, as shown by their methylation to give tertiary analogues. The structures hold broader implications for the placement of functional groups on concave molecular surfaces.
- O'Leary,Szabo,Svenstrup,Schalley,Luetzen,Schaefer,Rebek Jr.
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p. 11519 - 11533
(2007/10/03)
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- REACTIVITY OF THE ACIDS OF TRIVALENT PHOSPHORUS AND THEIR DERIVATIVES. PART I. REDUCTIVE DEBROMINATION IN THE REACTIONS OF THE >P-O- IONS WITH 2-BROMOESTERS
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The reaction of α-bromocarboxylates with sodium dialkyl (diaryl) phosphites as well as sodium salt of dibenzylphosphine oxide in THF and alcohols as the solvents is described.Debromination of the starting materials occurs.Probable mechanisms namely SET and X-philic substitution are discussed. Key words: α-Bromocarboxylates; debromination; dialkyl phosphites; diaryl phosphites; dibenzylphosphine oxide; Michaelis-Becker reaction; X-philic substitution.
- Dembkowski, Leszek,Rachon, Janusz
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- Synthesis of Analogues of 5-Iodo-2'-deoxyuridine-5'-diphosphate
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The synthesis of three types of diphosphate analogues of 5-iodo-2'-deoxyuridine-5'-diphosphate is reported.Routes are described to the 5'-phosphonoacetamido, the 5'-N-phosphonosulfamoyl and the 5'-O-sulfamoylcarbamoyl derivatives, 2, 3 and 4 starting from
- Jennings, L. John,Macchia, Marco,Parkin, Ann
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p. 2197 - 2202
(2007/10/02)
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- 4 Deoxy-4-methylene oleandomycin and derivatives thereof
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Derivatives of oleandomycin, its 11-trimethylsilyl ether and 11-trimethylsilyl-2'-alkanoyl esters and processes for preparation thereof wherein the L-oleandrosyl moiety is modified at the 4"-position to provide derivatives thereof wherein said moiety has
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