25070-80-8Relevant articles and documents
De novo synthesis of troc-protected amines: Intermolecular rhodium-catalyzed C-H amination with N-tosyloxycarbamates
Lebel, Helene,Kim, Huard
, p. 639 - 642 (2007)
The rhodium-catalyzed intermolecular C-H insertion of the nitrene derived from 2,2,2-trichloroethyl-N-tosyloxycarbamate proceeded in good to excellent yields to produce a variety of Troc-protected amines. With cyclic aliphatic alkanes, it is possible to use only 2 equiv of substrate, whereas the reaction with aromatic alkanes is run neat. Not only does the nitrene insertion proceed in benzylic, secondary, and tertiary C-H bonds but also primary C-H insertion products were obtained in good yields. Finally, the use of chiral rhodium catalysts to provide an enantioselective version of this process is discussed.
N-methylimidazole-catalyzed synthesis of carbamates from hydroxamic acids via the lossen rearrangement
Yoganathan, Sabesan,Miller, Scott J.
, p. 602 - 605 (2013/04/11)
An efficient, one-pot, N-methylimidazole (NMI) accelerated synthesis of aromatic and aliphatic carbamates via the Lossen rearrangement is reported. NMI is a catalyst for the conversion of isocyanate intermediates to the carbamates. Moreover, the utility of arylsulfonyl chloride in combination with NMI minimizes the formation of often-observed hydroxamate-isocyanate dimers during the sequence. Under the present conditions, lowering of temperatures is also possible, enabling a mild protocol.
N-tosyloxycarbamates as reagents in rhodium-catalyzed C-H amination reactions
Huard, Kim,Lebel, Helene
scheme or table, p. 6222 - 6230 (2009/05/27)
Metal nitrenes for use in C-H insertion reactions were obtained from N-tosyloxycarbamates in the presence of an inorganic base and a rhodium(II) dimer complex catalyst. The C-H amination reaction proceeds smoothly, and the potassium tosylate that forms as a byproduct is easily removed by filtration or an aqueous workup. This new methodology allows the amination of ethereal, benzylic, tertiary, secondary, and even primary C-H bonds. The intramolecular reaction provides an interesting route to various substituted oxazolidinones, whereas the intermolecular reaction gives trichloroethoxycarbonyl-protected amines that can be isolated with moderate to excellent yields and that cleave easily to produce the corresponding free amine. The development, scope, and limitations of the reactions are discussed herein. Isotopic effects and the electronic nature of the transition state are used to discuss the mechanism of the reaction.
