- Size-Driven Inversion of Selectivity in Esterification Reactions: Secondary Beat Primary Alcohols
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Relative rates for the Lewis base-mediated acylation of secondary and primary alcohols carrying large aromatic side chains with anhydrides differing in size and electronic structure have been measured. While primary alcohols react faster than secondary ones in transformations with monosubstituted benzoic anhydride derivatives, relative reactivities are inverted in reactions with sterically biased 1-naphthyl anhydrides. Further analysis of reaction rates shows that increasing substrate size leads to an actual acceleration of the acylation process, the effect being larger for secondary as compared to primary alcohols. Computational results indicate that acylation rates are guided by noncovalent interactions (NCIs) between the catalyst ring system and the DED substituents in the alcohol and anhydride reactants. Thereby stronger NCIs are formed for secondary alcohols than for primary alcohols.
- Mayr, Stefanie,Marin-Luna, Marta,Zipse, Hendrik
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p. 3456 - 3489
(2021/03/01)
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- In situ generation of nitrilium from nitrile ylide and the subsequent Mumm rearrangement: copper-catalyzed synthesis of unsymmetrical diacylglycine esters
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A novel in situ generation of nitrilium from a nitrile ylide and the subsequent Mumm rearrangement of carboxylic acid, nitrile, and diazo compounds gave various unsymmetrical diacylglycine esters in moderate to high yields. This copper-catalyzed cascade reaction enables one-pot generation of two C-N bonds, one C=O bond, and one C-H bond, with nitrogen as the only byproduct. The reaction has a broad functional-group tolerance, is rapid, easily scales up to the 100 mmol scale, and is insensitive to air and moisture.
- Chen, Jijun,Shao, Ying,Ma, Liang,Ma, Meihua,Wan, Xiaobing
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supporting information
p. 10723 - 10732
(2016/11/30)
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- Synthesis of symmetric anhydrides using visible light-mediated photoredox catalysis
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A new approach to anhydride formation is reported via activation of C-O bonds by the Vilsmeier-Haack reagent formed by Ru(bpy)3Cl2 and CBr4 in DMF. Various aryl and alkyl carboxylic acids are converted to the corresponding anhydrides in excellent yields.
- Konieczynska, Marlena D.,Dai, Chunhui,Stephenson, Corey R. J.
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supporting information; experimental part
p. 4509 - 4511
(2012/07/31)
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- Reaction of Diazonium Salts with Transition Metals. 4. Palladium(0)-Catalyzed Carboxylation of Arenediazonium Salts
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Various arylamines were converted to arenecarboxylic acids in good yields via their diazonium tetrafluoroborates by reaction with carbon monoxide (9 kg/cm2) in the presence of a palladium(0) catalyst and sodium acetate.Evidence is presented which supports the idea that mixed anhydrides are initial products in the carboxylation.
- Nagira, Kazuhiko,Kikukawa, Kiyoshi,Wada, Fumio,Matsuda, Tsutomu
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p. 2365 - 2368
(2007/10/02)
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