- Three-Component Aminoarylation of Electron-Rich Alkenes by Merging Photoredox with Nickel Catalysis
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A three-component 1,2-aminoarylation of vinyl ethers, enamides, ene-carbamates and vinyl thioethers by synergistic photoredox and nickel catalysis is reported. 2,2,2-Trifluoroethoxy carbonyl protected α-amino-oxy acids are used as amidyl radical precursors. anti-Markovnikov addition of the amidyl radical to the alkene and Ni-mediated radical/transition metal cross over lead to the corresponding 1,2-aminoarylation product. The radical cascade, which can be conducted under practical and mild conditions, features high functional group tolerance and broad substrate scope. Stereoselective 1,2-aminoarylation is achieved using a L-(+)-lactic acid derived vinyl ether as the substrate, offering a novel route for the preparation of protected enantiopure α-arylated β-amino alcohols. In addition, 1,2-aminoacylation of vinyl ethers is achieved by using an acyl succinimide as the electrophile for the Ni-mediated radical coupling.
- Jiang, Heng,Yu, Xiaoye,Daniliuc, Constantin G.,Studer, Armido
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supporting information
p. 14399 - 14404
(2021/05/26)
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- Preparation method of alicyclic and aromatic-aliphatic chloroformate
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The invention belongs to the technical field of fine chemistry, and in particular relates to a preparation method of alicyclic and aromatic-aliphatic chloroformate. The preparation method is characterized in that alicyclic alcohol chloroformate or aromatic-aliphatic alcohol chloroformate is obtained by taking alicyclic alcohol or aromatic-aliphatic alcohol and bis(trichlormethyl)carbonate as raw materials, taking organic base as a catalyst and reacting in an organic solvent under certain reaction temperature and certain reaction time, wherein molar ratio among the alicyclic alcohol or the aromatic-aliphatic alcohol, the bis(trichlormethyl)carbonate and the organic base is 1 to (0.4 to 1) to (1.2 to 3); experiment time and experiment temperature are different in two stages, in the first stage, the reaction temperature is -10 to 0 DEG C, and the reaction time is 2 to 5 hours; in the second stage, the reaction temperature is 0 to 25 DEG C, and the reaction time is 7 to 13 hours; a mass ratio between the organic solvent and the alicyclic alcohol or the aromatic-aliphatic alcohol is (10 to 25) to 1; residue in a reaction system is effectively treated, and reaction waste is also recycled and utilized. The preparation method disclosed by the invention has the characteristics of stable reaction, high reaction yield and product purity, environment protection of a reaction process, low production cost, less emission of three wastes, simpleness in preparation technology and easiness in industrialization.
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Paragraph 0062-0063; 0076-0077; 0078-0079
(2017/05/16)
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- (S)-(-)-N-(Pentafluorobenzylcarbamoyl)prolyl chloride: A chiral derivatisation reagent designed for gas chromatography/negative ion chemical ionisation mass spectrometry of amino compounds
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RATIONALE The synthesis of a novel chiral derivatisation reagent, (S)-(-)-N-(pentafluorobenzylcarbamoyl)prolyl chloride is described which is preferably useful for negative-ion chemical ionisation mass spectrometry. METHODS Preparation of the reagent followed a general strategy used to prepare enantioselective reagents based on the N-substitution of L-proline. Pentafluorobenzyl chloroformate smoothly reacted with L-proline to give the desired derivatisation reagent after conversion into the acyl chloride. The product was sufficiently pure to be used in the following steps without any additional purification. RESULTS The reagent was tested against selected chiral and non-chiral analytical targets. Chromatographic enantioseparation was at least equal to the commonly used (S)-(-)-N-(heptafluorobutyryl)prolyl derivatives. The derivatives exhibit excellent mass spectral properties under negative ion chemical ionisation, i.e. reduced fragmentation and thus high ion current for the targeted m/z during analysis. With electron ionisation, the fragmentation that occurs is mainly directed by the introduced group. Enantioseparation with gas chromatography/negative-ion chemical ionisation mass spectrometry of the derivatives was demonstrated for the enantiomers of amphetamine, α-aminocaprylic acid methyl ester and threo-methylphenidate. CONCLUSIONS The new derivatisation reagent shows highly improved mass spectral properties for negative-ion chemical ionisation mass spectrometry and is thus suitable for sensitive chiral detection of amino compounds. The reagent extends the applicability of dissociative resonance electron capture using pentafluorobenzyl derivatives to chiral analysis. Copyright
- Leis, Hans J.,Windischhofer, Werner
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experimental part
p. 592 - 598
(2012/06/29)
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- Synthesis of Highly Fluorinated Chloroformates and Their Use as Derivatizing Agents for Hydrophilic Compounds and Drinking-Water-Disinfection by-Products
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A rapid, safe, and efficient procedure was developed to synthesize, on a small scale, fluorinated chloroformates often required to perform analytical derivatizations. This new family of agents allows straightforward derivatization of highly polar compounds (with multiple hydroxy, carboxy, and amino substituents) in the aqueous phase, compatible with GC and GC/MS analysis. A goal of this work was to develop a derivatization procedure that would enable the detection and identification of highly polar disinfection by-products in drinking water.
- Vincenti, Marco,Ghiglione, Nicoletta,Valsania, Maria Carmen,Davit, Patrizia,Richardson, Susan D.
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p. 370 - 375
(2007/10/03)
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