(Tosylimino)phenyl-λ<sup>3</sup>-iodane as a Reagent for the Synthesis of Methyl Carbamates via Hofmann Rearrangement of Aromatic and Aliphatic Carboxamides
作者:Akira Yoshimura、Matthew W. Luedtke、Viktor V. Zhdankin
DOI:10.1021/jo300007c
日期:2012.2.17
A new, mild procedure for the Hofmann rearrangement of aromatic and aliphatic carboxamides using (tosylimino)phenyl-λ3-iodane, PhINTs, as a reagent is reported. Because of the mild reaction conditions, this method is particularly useful for the Hofmann rearrangement of substituted benzamides, which usually afford complex reaction mixtures with other hypervalent iodine oxidants. The mild reaction conditions
Kinetics and Mechanism of the Aminolysis of O-Methyl S-Aryl Thiocarbonates in Acetonitrile
作者:Hyuck-Keun Oh
DOI:10.5012/bkcs.2011.32.5.1539
日期:2011.5.20
The aminolysis of O-methyl S-aryl thiocarbonates with benzylamines are studied in acetonitrile at -45.0. The () values are in the range 0.62-0.80 with a negative cross-interaction constant, = -0.42, which are interpreted to indicate a concerted mechanism. The kinetic isotope effects involving deuterated benzylamine nucleophiles () are large, = 1.29-1.75, suggesting that the N-H(D) bond is partially
Hofmann Rearrangement of Carboxamides Mediated by Hypervalent Iodine Species Generated in Situ from Iodobenzene and Oxone: Reaction Scope and Limitations
作者:Aleksandra A. Zagulyaeva、Christopher T. Banek、Mekhman S. Yusubov、Viktor V. Zhdankin
DOI:10.1021/ol101993q
日期:2010.10.15
Alkylcarboxamides can be converted to the respective amines by Hofmann rearrangement using hypervalent iodine species generated in situ from PhI and Oxone in aqueous acetonitrile. On the basis of this reaction, a convenient experimental procedure for the preparation of alkylcarbamates using Oxone as the oxidant in the presence of iodobenzene in methanol has been developed. An efficient method for direct
l-Proline–TBAB-catalyzed phosgene free synthesis of methyl carbamates from amines and dimethyl carbonate
作者:Subodh Kumar、Suman L. Jain
DOI:10.1039/c3nj00643c
日期:——
The reaction of amines and dimethyl carbonate (DMC) in the presence of catalytic amounts of L-proline and tetrabutylammonium bromide (TBAB) afforded methyl carbamates in good to excellent yields under mild conditions. The presence of both L-proline and TBAB co-catalysts is vital for this transformation.
Manganese Catalyzed Hydrogenation of Carbamates and Urea Derivatives
作者:Uttam Kumar Das、Amit Kumar、Yehoshoa Ben-David、Mark A. Iron、David Milstein
DOI:10.1021/jacs.9b05591
日期:2019.8.21
We report the hydrogenation of carbamates and ureaderivatives, two of the most challenging carbonyl compounds to be hydrogenated, catalyzed for the first time by a complex of an earth-abundant-metal. The hydrogenation reaction of these CO2-derived compounds, cata-lyzed by a manganese pincer complex, yields methanol in addition to amine and alcohol, which makes this methodology a sustainable two-step
我们报告了氨基甲酸酯和尿素衍生物的氢化,这两种最具挑战性的羰基化合物被氢化,首次由地球丰富的金属络合物催化。这些 CO2 衍生化合物的氢化反应在锰钳络合物的催化下产生甲醇以及胺和醇,这使得该方法成为将 转化为甲醇的可持续两步路线,包括碱-金属催化剂。此外,氢化在温和压力(20巴)下进行。我们的观察结果支持涉及 Mn-H 络合物的氢化机制。基于信息丰富的机械实验提出了一个合理的催化循环。