- Base-free oxidation of alcohols enabled by nickel(ii)-catalyzed transfer dehydrogenation
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An efficient nickel(ii)-catalyzed transfer dehydrogenation oxidation of alcohols is reported that relies on cyclohexanone as the formal oxidant and does not require the use of an external base. The synthetic utility of this protocol is demonstratedviathe facile oxidation of structurally complicated natural products.
- Ye, Danfeng,Liu, Zhiyuan,Sessler, Jonathan L.,Lei, Chuanhu
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supporting information
p. 11811 - 11814
(2020/10/13)
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Functionalisation in 2 position of benzenes 1,3-disubstituted by para-directing groups has been investigated, involving 2-trimethylsilylated intermediates when the classical methods (particularly these involving the anion in 2 position) are ineffective. Thus 2-trimethylsilyl derivatives of 1,3-dihalo- or 1,3-dimethoxybenzene have been prepared in good yields. Their conversion into the corresponding 1,2,3-trisubstituted benzenes has been conveniently performed upon acetylation, iodination or sulfonation, except in the case of the sulfonation of the 1,3-dimethoxylated compound in which the ipso effect of the silyl group is surpassed by the directing effect of the methoxy substituents. In contrast, whith the same substrate, cyanation in position 2 was successfully carried out using chlorosulfonyl isocyanate: to our knowledge this reaction is the first example of substitution of a trimethylsilyl by a cyano group in the aromatic series.
- Bennetau, Bernard,Rajarison, Florent,Dunogues, Jacques,Babin, Pierre
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p. 10843 - 10854
(2007/10/02)
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- Process for the manufacture of ketones
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Ketones are prepared by reacting carboxylic acid halides, in particular carboxylic acid chlorides, with aluminum-alkyl compounds, optionally in the presence of an aluminum trihalide, in methylene chloride as the solvent, at a temperature between about 20° and about 100° C., preferably between about 30° and about 60° C., more preferably of about 40° C. which is the reflux temperature of the methylene chloride. When operating at a temperature above approximately 40° C., pressure higher than atmospheric is applied. The reaction mixture is worked up in usual manner, suitably by decomposition with water followed by distillation.
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