- Nickel-Catalyzed Decarboxylative Alkenylation of Anhydrides with Vinyl Triflates or Halides
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Decarboxylative cross-coupling of aliphatic acid anhydrides with vinyl triflates or halides was accomplished via nickel catalysis. This methodology works well with a broad array of substrates and features abundant functional group tolerance. Notably, our approach addresses the issue of safe and environmental installation of methyl or ethyl group into molecular scaffolds. The method possesses high chemoselectivity toward alkyl groups when aliphatic/aromatic mixed anhydrides are involved. Furthermore, diverse ketones could be modified with our strategy.
- Chen, Hui,Sun, Shuhao,Liao, Xuebin
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p. 3625 - 3630
(2019/05/24)
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- Palladium/Rhodium Cooperative Catalysis for the Production of Aryl Aldehydes and Their Deuterated Analogues Using the Water–Gas Shift Reaction
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A novel Pd/Rh dual-metallic cooperative catalytic process has been developed to effect the reductive carbonylation of aryl halides in moderate to good yield. In this reaction, water is the hydride source, and CO serves both as the carbonyl source and the terminal reductant through the water–gas shift reaction. The catalytic generation of the Rh hydride allows for the selective formation of highly hindered aryl aldehydes that are inaccessible through previously reported reductive carbonylation protocols. Moreover, aldehydes with deuterated formyl groups can be efficiently and selectively synthesized using D2O as a cost-effective deuterium source without the need for presynthesizing the aldehyde.
- Ibrahim, Malek Y. S.,Denmark, Scott E.
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p. 10362 - 10367
(2018/07/31)
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- Synthesis, NMR Spectra, and Photoelectron Spectra of Cyclic Ketene N,X-Acetals (2-Alkylidene-N-heterocycles)
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Deprotonation by sodium hydride of the N-methyl-2-alkylazolium salts 10c, 14-16, and 18 and of the perimidinium salt 20 as well affords the corresponding ketene N,X-acetals 1c, 3-5, 7 and 8 as air-sensitive distillable oils or low-melting crystals.The α-c
- Quast, Helmut,Ach, Manfred,Kindermann, Markus K.,Rademacher, Paul,Schindler, Michael
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p. 503 - 516
(2007/10/02)
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- Friedel-Crafts Reaction of 2-Methylfuran with Saturated and α,β-Unsaturated Acid Anhydrides
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2-Methylfuran (5) reacts with the saturated acid anhydrides 16 - 26 in the presence of SnCl4 to give the 2-acyl-5-methylfurans 37 - 47 selectively.The unsaturated anhydrides 27 - 32, however, yield mixtures which only in the case of senecioic acid anhydride (29) contain the respective primary product 48.Subsequent reactions lead to the addition products 55 (from 27) and 56 (from 29), and to (E,Z)-mixtures of their enol esters 57 - 62 which could partially be separated and assigned. - The olfactory properties of 2, 37 - 48, 50, 52, and 53 were investigated.
- Scholz, Stefan,Marschall-Weyerstahl, Helga,Weyerstahl, Peter
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p. 1935 - 1950
(2007/10/02)
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- Synthesis of Analogues of the Carboxyl Protease Inhibitor Pepstatin. Effect of Structure in Subsite P3 on Inhibition of Pepsin
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A series of pepstatin analogues having minimum structural requirements for tight-binding inhibition has been synthesized and tested on porcine pepsin.Subtle changes in the geometry and size of side chains at the valine-1 position of pepstatin were found to dramatically affect inhibitor potency as well as the type of kinetic behavior observed.The inhibitors reported here can be grouped into two categories: the more potent inhibitors are slow-binding inhibitors, i.e., exhibit slow, time-dependent inhibition; the weaker inhibitors, with Ki values greater than 10-8M, are not time-dependent inhibitors.A minimum kinetic mechanism is proposed to account for the observed kinetic behavior.
- Rich, Daniel H.,Bernartowicz, Michael S.
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p. 791 - 795
(2007/10/02)
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- Trimethylsilyl Cyanide - A Reagent for Umpolung, VIII. Derivatives of 2-(Trimethylsilyloxy)-2-propenenitrile. Syntheses and General Properties
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Rather different derivatives of the new title compuond 7 were synthesized by routes A - H (Table 2 and 3).The effects of substituents and reaction routes on the E/Z ratios (NMR) is discussed.Replacement of SiMe3 in 7 by RCO- and MeSO2- yields other alkenes with donor (O - X) and acceptor groups (CN) at the same C-atom.Their opposite effects on the β-C-atom is estimated from the corresponding 1H- and 13C-NMR signals.
- Hertenstein, Ulrich,Huenig, Siegfried,Reichelt, Helmut,Schaller, Rainer
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p. 261 - 287
(2007/10/02)
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