Copper-Catalyzed Alkene Aziridination with N-Tosyloxycarbamates
摘要:
Pyridine copper complexes were found as active catalysts for the intramolecular aziridination of allylic N-tosyloxycarbamates and the intermolecular aziridination of styrenes with trichloroethyl N-tosyloxycarbamates. Free aziridines were easily obtained by basic deprotection of the trichloroethyl group.
styrenes. Subsequent ring-opening reactions of styrene-derived aziridines at the benzylic position were observed with various oxygen and nitrogen nucleophiles under Lewis acid catalysis affording the corresponding products with complete inversion of stereochemistry. The strategy was used to synthesize the β-blocker, (R)-nifenalol.
Intermolecular aromatic C(sp2)–H amination promoted by neutral rhodium nitrenoids has been developed. The reactions proceeded with various oxygen-substituted arenes (1.5 equiv.) in a chemo- and regioselective manner. The aromatic C(sp2)–H amination took place at the para position of the oxygen substituent in the presence of benzylic C(sp3)–H bonds and/or C(sp3)–H bonds α to ethereal oxygen.
De Novo Synthesis of Troc-Protected Amines: Intermolecular Rhodium-Catalyzed C−H Amination with <i>N</i>-Tosyloxycarbamates
作者:Hélène Lebel、Kim Huard
DOI:10.1021/ol062953t
日期:2007.2.1
intermolecular C-Hinsertion 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
<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
Osmium-Catalyzed Vicinal Oxyamination of Alkenes by <i>N</i>-(4-Toluenesulfonyloxy)carbamates
作者:Masruri、Anthony C. Willis、Malcolm D. McLeod
DOI:10.1021/jo301372y
日期:2012.10.5
N-(4-Toluenesulfonyloxy)carbamates based on a range of common amine protecting groups serve as preformed nitrogen sources in the intermolecular osmium-catalyzedoxyamination reaction of a variety of mono-, di-, and trisubstituted alkenes. The reactions occur with low catalyst loadings and good yields and afford high regioselectivity for unsymmetrically substituted alkenes.