- Electro-mediated PhotoRedox Catalysis for Selective C(sp3)–O Cleavages of Phosphinated Alcohols to Carbanions
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We report a novel example of electro-mediated photoredox catalysis (e-PRC) in the reductive cleavage of C(sp3)?O bonds of phosphinated alcohols to alkyl carbanions. As well as deoxygenations, olefinations are reported which are E-selective and can be made Z-selective in a tandem reduction/photosensitization process where both steps are photoelectrochemically promoted. Spectroscopy, computation, and catalyst structural variations reveal that our new naphthalene monoimide-type catalyst allows for an intimate dispersive precomplexation of its radical anion form with the phosphinate substrate, facilitating a reactivity-determining C(sp3)?O cleavage. Surprisingly and in contrast to previously reported photoexcited radical anion chemistries, our conditions tolerate aryl chlorides/bromides and do not give rise to Birch-type reductions.
- Barham, Joshua P.,K?nig, Burkhard,Karl, Tobias A.,Reiter, Sebastian,Tian, Xianhai,Yakubov, Shahboz,de Vivie-Riedle, Regina
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p. 20817 - 20825
(2021/08/18)
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- Isoxazoline derivative and application thereof in agriculture
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The invention provides an isoxazoline derivative and application of the isoxazoline derivative in agriculture. Specifically, the invention provides a compound as shown in a formula (I) or a stereoisomer, nitrogen oxide or salt of the compound as shown in the formula (I), and a preparation method thereof. In the formula (I), R1, R2, R3, R4, n, R5, R6, R7, R8 and Acy are as defined in the invention.Further, the invention provides compositions containing these compounds and use thereof in agriculture, particularly as herbicidal active ingredients for controlling unwanted plants.
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Paragraph 0233; 0239-0241
(2020/11/25)
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- Epoxides, amino alcohols, and aziridines as key intermediates in the asymmetric synthesis of (S)-fenfluramine
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The epoxides 3E, 3Z and 8 were obtained from the isomeric alkenes 2E, 2Z and 7.The epoxides were ring-opened by ethylamine in ethanol yielding mixtures of the amino alcohols 4E and 11E, 4T and 11T, and 9, respectively, which were transformed into the aziridines 5trans, 5cis and 12.The regiospecific Pd/C-catalyzed reduction of these aziridines gave fenfluramine 1.The three epoxides 3trans, 3cis and 8 were reduced regiospecifically into 1-propan-2-ol 6, a potent precursor to fenfluramine 1.The validity of our method for asymmettric synthesis has been demonstrated by a synthesis of (S)-fenfluramine 1 starting from the amino alcohol (S)-9.Keyword - fenfluramine / asymmetric synthesis / epoxide / amino alcohol / aziridine / regiospecific catalytic hydrogenation / 1-propan-2-ols
- Goument, B.,Duhamel, L.,Mauge, R.
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p. 459 - 466
(2007/10/02)
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- Syntheses of (S)-fenfluramine from (R) or (S)-1-propan-2-ol
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(R) and (S)-1-propan-2-ol 3 are useful intermediates in the synthesis of fenfluramine (S)-1.They can be obtained from optically active propylene oxide (R) or (S)-7.The alcohol (R)-3 was transformed in two steps into (S)-fenfluramine using the action of ethylamine on a sulfonate (R)-4.We describe a new one-pot synthesis for (S)-fenfluramine from the azide (S)-5, which was obtained from the alcohol (R)-3 in two steps.We also propose an original and rapid procedure to transform the alcohol (S)-3 into (S)-fenfluramine via the chloride (R)-14 and the azide (S)-5, without preliminary inversion of the alcohol.All of these reactions have been achieved without any loss of chirality.Keywords - 1-propan-2-ol / fenfluramine / asymmetric synthesis / chiral methyloxirane / nucleophilic substitution
- Goument, B.,Duhamel, L.,Mauge, R.
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p. 450 - 458
(2007/10/02)
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