Palladium-Catalyzed β-Mesylation of Simple Amide via Primary sp3 C-H Activation
A β-mesylation of primary sp3 C-H bonds from simple amides with methanesulfonic anhydride (Ms2O) has been established successfully at 80 °C in a Pd(OAc)2 (catalyst)/K2S2O8 (oxidant)/CF3CH2OH (solvent) system. These amide substrates involve N-monosubstituted linear, branch, or cyclic alkanes, and electron-deficient benzyl compounds. The β-mesylated amide products can be converted easily to β-fluoroamides or β-lactams through inter- or intramolecular SN2 processes.
Palladium-catalyzed β-acyloxylation of simple amide via sp3 C-H activation
β-Acyloxy amides are prepared in moderate to high yields by palladium-catalyzed acyloxylation of primary sp3 C-H bonds from simple amides without any special directing group. A catalytic system of Pd(OAc)2/CF3CO2H/ K2S2O8 is available to various amides with N-substituted by linear alkanes, cyclic alkanes, and electron-deficient benzyl compounds in this reaction. Acyloxylated products could be transformed easily to the corresponding β-hydroxy amides.
Zhou, Lihong,Lu, Wenjun
supporting information
p. 508 - 511
(2014/04/03)
Kinetics and mechanism of aminolysis of phenyl acetates and phenyl trimethylacetates in dimethyl suldoxide
Kinetic studies have been carried out on the reactions of phenyl acetates and phenyl trimethylacetates in dimethyl sulfoxide.The rate ratios between the two acyl compounds, and the positive sign and large magnitude of the cross-interaction constants, ρXZ, between substituents X in the nucleophile and Z in the leaving group are considered to favour the rate-limiting expulsion of aryl oxide from the tetrahedral intermediate T+/-.The aprotic solvent used makes the proposed mechanism with a cyclic transition state more attractive especially in view of the greater charge dispersion and assistance to leaving group departure provided in such a structure.
Koh, Han Joong,Kim, Seung Il,Lee, Byung Choon,Lee, Ikchoon
p. 1353 - 1358
(2007/10/03)
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