- Access to Diarylmethanols by Wittig Rearrangement of ortho-, meta-, and para-Benzyloxy- N-Butylbenzamides
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The N-butyl amide group, CONHBu, has been found to be an effective promoter of the [1,2]-Wittig rearrangement of aryl benzyl ethers and thus allow the two-step synthesis of isomerically pure substituted diarylmethanols starting from simple hydroxybenzoic acid derivatives. The method is compatible with a wide range of functional groups including methyl, methoxy, and fluoro, although not with nitro and, unexpectedly, is applicable to meta as well as ortho and para isomeric series.
- Aitken, R. Alan,Harper, Andrew D.,Inwood, Ryan A.,Slawin, Alexandra M. Z.
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p. 4692 - 4701
(2022/04/07)
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- Copper-Assisted Synthesis of 2-Hydroxyphenyl-1,2-diones from Phenols and 2-Oxoaldehydes
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An efficient copper(II)-catalyzed protocol for the ortho-functionalization of phenols was developed. A wide variety of 2-oxoaldehydes and phenols were tolerated, and the corresponding 2-hydroxyphenyl-1,2-diones were afforded in appreciable yields.
- Battini, Narsaiah,Battula, Satyanarayana,Ahmed, Qazi Naveed
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supporting information
p. 658 - 662
(2017/01/18)
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- Aminocatalytic cross-coupling approach via iminium ions to different C-C bonds
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Given the attractive ability of iminium ions to functionalize molecules directly at ostensibly unreactive positions, the reactivity of iminium ions, in which an α CH2 group is replaced by C=O was explored. Background studies on the ability of such iminium cations to promote reactions via an iminium-catalyzed or iminium-equivalent pathway are apparently unavailable. Previously, tandem cross-coupling reactions were reported, in which an iminium ion undergoes nucleophilic 1,2-addition to give a putative three-component intermediate that abstracts a proton in situ and undergoes self-deamination followed by unprecedented DMSO/ aerobic oxidation to generate a-ketoamides. However, later it was observed that iminium ions can generate valuable α-ketoamides through simple aerobic oxidation. In all reactions, iminium ions were generated in situ by reaction of 2-oxoaldehydes with secondary amines.
- Mupparapu, Nagaraju,Battini, Narsaiah,Battula, Satyanarayana,Khan, Shahnawaz,Vishwakarma, Ram A.,Ahmed, Qazi Naveed
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supporting information
p. 2954 - 2960
(2015/02/05)
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- Iron-catalyzed ortho-selective functionalization of phenols: A straightforward strategy towards the 2′-hydroxyphenyl-1,2-dione skeleton
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An iron-catalyzed ortho-functionalization of phenols was developed. The reactions of simple phenols with α-hydroxy ketones provide a novel and efficient method to construct 2′-hydroxyphenyl-1,2-dione derivatives. An iron-catalyzed ortho-functionalization of phenols was developed. The reactions of simple phenols with α-hydroxy ketonesprovide a novel and efficient method to construct 2′-hydroxyphenyl-1,2-dione derivatives.
- Guo, Xingwei,Li, Wenjuan,Li, Zhiping
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supporting information; experimental part
p. 5787 - 5790
(2011/01/04)
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- Synthesis of unsymmetrical benzil licoagrodione
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(Chemical Equation Presented) A synthesis of unsymmetrical 1,2-diarylethane-1,2-dione is reported involving the intramolecular cyclization of anionic benzylic ester of the aryl benzyl ether followed by oxidation employing dioxirane. With the use of microwave irradiation, licoagrodione was prepared from Claisen rearrangement of the corresponding allyl phenyl ether 1,2-diketone readily available from the Lindlar's reduction of the corresponding alkyne derivative. Subsequent removal of protecting groups then furnished the desired product.
- Worayuthakarn, Rattana,Boonya-udtayan, Sasiwadee,Arom-oon, Eakarat,Ploypradith, Poonsakdi,Ruchirawat, Somsak,Thasana, Nopporn
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supporting information; experimental part
p. 7432 - 7435
(2009/04/18)
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- The confined cavity of a coordination cage suppresses the photocleavage of α-diketones to give cyclization products through kinetically unfavorable pathways
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(Figure Presented) It's a trap: The photochemical homolytic cleavage of an α-diketone leading to degradation products was suppressed through the encapsulation of the diketone in a self-assembled cage. Instead, intramolecular cyclization products were formed through otherwise unfavorable (kinetically hidden) reaction pathways. This provides an approach to find new reactions of photolabile compounds that had been abandoned because of predominant cleavage reactions.
- Furusawa, Takahito,Kawano, Masaki,Fujita, Makoto
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p. 5717 - 5719
(2008/09/16)
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- Intramolecular Ketene Cycloadditions. Synthesis of Isoflavones and 3-Aroylbenzofurans
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The conversion of 2-(carboxyalkoxy)benzils to the corresponding phenoxyketenes to an intramolecular ketene cycloaddition to ultimately yield isoflavones and/or 3-aroylbenzofurans.The ketenes may be generated by the classical dehydrochlorination of the acid chloride or by using Perkin reaction conditions, sodium acetate in refluxing acetic anhydride.The initial cycloaddition products are the corresponding β-lactones, which may decarboxylate to the isolated isoflavones and/or 2-aroylbenzofurans.The product distributions are dependent upon the substitution pattern in the orginal benzil acids.
- Brady, William T.,Gu, Yi-Qi
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p. 1353 - 1356
(2007/10/02)
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- Studies in the chemistry of chromone epoxides
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Chromones and isoflavones, but not flavones, were epoxidized by alkaline hydrogen peroxide. 3-Substituted chromone epoxides were considerably more stable than others; one isoflavone epoxide was converted into a fluorohydrin, another into a 1,2-diol. The latter is a 2-hydroxychromanone and a similarly structured compound was obtained by the cyclisation of 2'-benzoyloxy-2,2-dibromoacetophenone. Acid-catalysed ring-opening of chromone epoxides occurred regioselectively yielding 3-hydroxychromanones. Base-catalysed ring-opening also occurred regioselectively but at the 3-position. Acid- and base-catalysed hydrolysis of 2-methy-lisoflavone epoxide resulted in cleavage of both heterocyclic rings, yielding, respectively, a 1,3- and a 1,2-diketone. This epoxide formed a cyclic sulphate with sulphuric acid.
- Donnelly, John A.,Keegan, John R.,Quigley, Killian
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p. 1671 - 1680
(2007/10/02)
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