Gold(III)-Catalyzed Nitrene Insertion into Aromatic and Benzylic C−H Groups

Abstract

General: All reagents were bought from commercial sources and used as received unless otherwise noted. All reactions were performed under an inert N 2 atmosphere and all solvents were distilled before use unless otherwise noted. CH 2 Cl 2 was distilled over CaH 2 . Chromatographic purification of products was accomplished by using forced-flow chromatography on EM Science Geduran silica gel 60 (35-75 µm). Thin layer chromatography was performed on EM Science silica gel 60 F254 plates (250 µm). Visualization of the developed chromatogram was accomplished by UV lamp and/or by staining with aqueous potassium permanganate/K 2 CO 3 solutions, or aqueous ceric ammonium molybdate (CAM) solutions. Nuclear magnetic resonance (NMR) spectra were acquired on Bruker DRX-500/400 operating at 125/100 MHz for 1 H and 13 C, respectively; residual protio solvent signals were used as internal standards for calibration purposes. Data for 1 H NMR are reported as follows: chemical shift (ppm), multiplicity (s, singlet; d, doublet; t, triplet; q, quartet; m, multiplet), integration, coupling constant (Hz). Freshly prepared samples (ca. 1 mg/mL in CH 2 Cl 2 ) were subject to electrospray mass spectra (ESI-MS) analysis. A 5 μL sample was injected by flow injection with the use of an autosampler and the data were recorded on with an m/z range of 0-3000. Both the nebulizing and drying gas are purified nitrogen. Typical instrumental parameters were: drying gas temperature 350 °C, nebulizer pressure 35 psi, drying gas flow 12.0 L/min, and fragmentor voltage 0 or 70 V.

Ohne dirigierende Gruppen: übergangsmetallkatalysierte C‐H‐Aktivierung einfacher Arene

“…[108,109] In Gegenwart der Nitrenvorstufe PhI=NNs (Ns = para-Nitrosulfonyl) und 2 Mol-% AuCl 3 konnten aromatische Substrate mit drei oder mehr Alkylsubstituenten in bis zu 90 % Ausbeute zu den entsprechenden Anilinen umgesetzt werden (Schema 26). Im Vergleich zu verwandten Kupfer-katalysierten Reaktionen [110] wurden die meisten Substrate hierbei mit guten Selektivitäten an ihren Aryl-C-H-Bindungen funktionalisiert.…”

“…Kupfer-katalysierte Hydroxylierung halogenierter Arene mit Luft von Lei et al [107] Schema 26. Gold-katalysierte Aminierung von Arenen mit PhI=NNs von He et al [108] Schema 27. Gold-katalysierte Aminierung von Arenen mit Azodicarboxylaten von Zhang et al [111] Direkte Kreuzkupplungen…”

Activation of Carbon−Hydrogen and Hydrogen−Hydrogen Bonds by Copper−Nitrenes: A Comparison of Density Functional Theory with Single- and Multireference Correlation Consistent Composite Approaches

“…22 He and co-workers also reported C-H bond activation at room temperature using gold-catalyzed nitrene insertion. 23 They found that, for C-H bond activation, a nearby aromatic C-H bond is needed, presumably to "direct" the activation/insertion event. Copper-scorpionate catalysts (i.e., Tp Br3 Cu(NCMe)) have been reported by Perez and co-workers to aminate C-H bonds.…”

Platinum(II)‐Catalyzed Intramolecular Cyclization of o‐Substituted Aryl Alkynes through sp3 CH Activation

“…[8] We tested both Ph 3 PAuCl and AuCl 3 for the reaction shown in Table 1. This reaction could occur but yields were low (13 and 17 %, respectively).…”

“…Both methyl-and ethyl-substituted substrates failed to yield products ( [c] 13 PtCl 2 (10.0) CuBr (2.0) 82 [c] 14 PtCl 2 (10.0) CuBr(1.0) 66 [c] 15 entries 2 and 3); reactions with substrates having weak CÀH bonds proceeded smoothly, to afford the corresponding indene derivatives with good yields and high selectivity ( Table 2, entries 1,[4][5][6][7][8]. This reaction tolerates functional groups, such as methyl, methoxy, and chloride, at different positions of the aromatic ring.…”