<i>N</i>‐Tosyloxycarbamates as Reagents in Rhodium‐Catalyzed CH Amination Reactions
作者:Kim Huard、Hélène Lebel
DOI:10.1002/chem.200702027
日期:2008.7.7
nitrenes for use in C-Hinsertion 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
The amino-functionalization of tertiary, secondary and benzylic C–H bonds of tethered carbamates and sulfamates by iodosobenzene is catalyzed by CuI-diimine complexes in moderate to good yield. Employing homochiral imine-Cucatalysts affords oxazolidinones and oxathiazinanes with modest enantioselectivity.
Herein, we report the development of a tailored cobalt catalyst system of Cp*Co(III)(LX) toward intramolecular C-H nitrene insertion of azidoformates to afford cyclic carbamates. The cobalt complexes were easy to prepare and bench-stable, thus offering a convenient reaction protocol. The catalytic reactivity was significantly improved by the electronic tuning of the bidentate LX ligands, and the observed
<i>N-</i>Tosyloxycarbamates as a Source of Metal Nitrenes: Rhodium-Catalyzed C−H Insertion and Aziridination Reactions
作者:Hélène Lebel、Kim Huard、Sylvain Lectard
DOI:10.1021/ja0552850
日期:2005.10.1
N-tosyloxycarbamates to generate metal nitrenes which undergo intramolecular C-H insertion or aziridination reaction is described. Aliphatic N-tosyloxycarbamates produce oxazolidinones with high yields and stereospecificity through insertion in benzylic, tertiary, and secondary C-H bonds. Intramolecular aziridination occurs with allylic N-tosyloxycarbamates to produce aziridines as single diastereomers
Selective intramolecular alkane oxidations: an RhII carboxylate catalyzed C-H amination reaction facilitates the preparation of 1,2-amino alcohols from primary carbamates. The reaction is stereospecific, providing access to chiral α-branched amines from optically pure starting materials with no loss in enantiomeric excess.