Catalytic Olefin Hydroamidation Enabled by Proton-Coupled Electron Transfer
摘要:
Here we report a ternary catalyst system for the intramolecular hydroamidation of unactivated olefins using simple N-aryl amide derivatives. Amide activation in these reactions occurs via concerted proton-coupled electron transfer (PCET) mediated by an excited state iridium complex and weak phosphate base to furnish a reactive amidyl radical that readily adds to pendant alkenes. A series of H-atom, electron, and proton transfer events with a thiophenol cocatalyst furnish the product and regenerate the active forms of the photocatalyst and base. Mechanistic studies indicate that the amide substrate can be selectively homolyzed via PCET in the presence of the thiophenol, despite a large difference in bond dissociation free energies between these functional groups.
situ reacted with aldehydes to give conjugated dienes in good yields in the presence of tributylphosphine and a catalytic amount of Pd(PPh3)4. This method proved to be suitable for the preparation of polyene compounds such as carotenoids.
A series of N-substituted aryl and alkylcarbamates (RNHCOOR'; R: aryl, alkyl; R': aryl, alkyl) was prepared and screened for inhibitory activity toward the germination of oat seeds. The activity of each compound was compared with that of chlorpropham (isopropyl 3-chlorocarbanilate). Some of the synthetic carbamates possessing the N-(phenylthio)methyl group, PhSCH2NHCOOR', showed inhibitory activity
Aminoacylation of Alkenes by Cooperative NHC and Photoredox Catalysis
作者:Lena Lezius、Jannik Reimler、Armido Studer、Nadine Döben、Michael Hamm、Constantin G. Daniliuc
DOI:10.1055/a-2145-8697
日期:2024.3
the combination of these two catalytic modes. The key step is a radical/radical cross-coupling between a persistent ketylradical and a transient benzylic or aliphatic C-radical, which is generated through radical cyclization of an oxidatively formed amidyl radical. Several carbamates, amides and sulfonamides containing an alkene moiety and different acyl fluorides can be used as substrates. The resulting
Catalytic Olefin Hydroamidation Enabled by Proton-Coupled Electron Transfer
作者:David C. Miller、Gilbert J. Choi、Hudson S. Orbe、Robert R. Knowles
DOI:10.1021/jacs.5b09671
日期:2015.10.28
Here we report a ternary catalyst system for the intramolecular hydroamidation of unactivated olefins using simple N-aryl amide derivatives. Amide activation in these reactions occurs via concerted proton-coupled electron transfer (PCET) mediated by an excited state iridium complex and weak phosphate base to furnish a reactive amidyl radical that readily adds to pendant alkenes. A series of H-atom, electron, and proton transfer events with a thiophenol cocatalyst furnish the product and regenerate the active forms of the photocatalyst and base. Mechanistic studies indicate that the amide substrate can be selectively homolyzed via PCET in the presence of the thiophenol, despite a large difference in bond dissociation free energies between these functional groups.