- Radical Behavior of CO2 versus its Deoxygenation Promoted by Vanadium Aryloxide Complexes: How the Geometry of Intermediate CO2-Adducts Determines the Reactivity.
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The reactivity of carbon dioxide with vanadium(III) aryloxo complexes has been investigated. The formation of either carbon monoxide or incorporation into the ligand system with the ultimate formation of organic ester was observed depending on the overall
- Viasus, Camilo J.,Alderman, Nicholas P.,Licciulli, Sebastiano,Korobkov, Ilia,Gambarotta, Sandro
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- Dimesityldioxirane
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The preparative scale synthesis of dimesityldioxirane (5) via oxidation of dimesitylcarbene (6) is described. The dioxirane was obtained as colorless crystalline material, completely stable at -20 °C and characterized by spectroscopic methods, X-ray crystallography, and DFT calculations (B3LYP/6-31G(d)). The molecule shows approximately local C2 symmetry with the mesityl rings twisted by ca. 60°. The experimental structural parameters, e.g., the O-O distance of 1.503 A?, are in good agreement with the theoretical values. The relief of steric strain caused by the mesityl groups is discussed in terms of the geometric distortion of the three-membered ring and the mesityl groups. Conformational features of 5 in solution are nicely reflected by measured and calculated (SOS-DFPT) NMR chemical shifts.
- Sander, Wolfram,Schroeder, Kerstin,Muthusamy, Sengodagounder,Kirschfeld, Andreas,Kappert, Wilhelm,Boese, Roland,Kraka, Elfi,Sosa, Carlos,Cremer, Dieter
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p. 7265 - 7270
(2007/10/03)
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- Copper Ion Promoted Esterification of S-2-Pyridyl Thioates and 2-Pyridyl Esters. Efficient Methods for the Preparation of Hindered Esters
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The esterification of the S-2-pyridyl thioates and 2-pyridyl esters with alcohols in acetonitrile is greatly facilitated by the addition of cupric bromide and copper ion is observed to catalyze the reaction.The ester formation is found to be sensitive to solvents, metal salts, and reaction temperatures.The esterification of S-2-pyridyl thioates is much more rapid than the esterification of 2-pyridyl esters under the reaction conditions employed.This method is exceedingly effective in the preparation of sterically hindered esters and has advantages over known methods in many respects such as high yields, the mildness of the reaction, and the rapidity of the reaction.
- Kim, Sunggak,Lee, Jae In
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p. 1712 - 1716
(2007/10/02)
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