Pd(II) catalyzed acetoxylation of arenes with iodosyl acetate

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

“…Basierend auf früheren Arbeiten mit Dichromaten [99] und Peroxodisulfaten als Oxidationsmittel [100] beschrieben Yoneyama und Crabtree 1996 einen einfach durchführbaren Prozess zur aromatischen Acetoxylierung unter Verwendung von Diacetoxyiodbenzol (PIDA). [101] Sanford und Mitarbeiter fanden kürzlich mit dem Einsatz eines Pd(OAc) 2 /Pyridin-Katalysatorsystems deutlich bessere Reaktionsbedingungen für diese Reaktion. [102,103] Das Metall/ Ligand-Verhältnis hatte einen starken Einfluss auf die Effizienz der Reaktion, die mit 0.9 ¾quivalenten Pyridin pro Pd(OAc) 2 -¾quivalent die hçchsten Ausbeuten der acetoxylierten Produkte lieferte.…”

Reversible oxidative addition of a diaryl diselenide to a diorganopalladium(II) complex, carbon–selenium bond formation at palladium(IV), and structural studies of palladium(II) and platinum(IV) selenolates

“…Formation of carbon(sp 2 )-heteroatom bonds by reductive elimination from Pd(IV) centres has been proposed in catalytic processes for C-O bond formation [1][2][3]. Model reactions relevant to this catalysis have been reported, but coupling from a Pd(IV) intermediate containing both Pd-C and Pd-O bonds has not been detected [4].…”

“…Crystals of 5 and 10 Á CHCl 3 were obtained by recrystallisation from CHCl 3 /diethyl ether and CH 2 Cl 2 / diethyl ether, respectively, and full spheres of CCD areadetector diffractometer data were measured (Bruker AXS instrument, 2h max ¼ 58°, x-scans, monochromatic Mo Ka radiation, k ¼ 0:7107 3 A; T ca. 153 K) yielding N ðtotalÞ reflections, merging to N unique (R int cited) after ÔempiricalÕ/multiscan absorption correction (proprietary software), N o with F > 4rðF Þ considered ÔobservedÕ and used in the full-matrix least squares refinements, refining anisotropic displacement parameter forms for the nonhydrogen atoms, (x; y; zU iso ) H being included and constrained at estimated values.…”

Study of the Transient Reactive Pd(IV) Intermediate in the Pd(OAc)2‐Catalyzed Oxidative Coupling Reaction System by Electrospray Ionization Tandem Mass Spectrometry

“…Crabtree et al [1] reported the first Pd(OAc) 2 -catalyzed acetoxylation of arenes with the terminal oxidant PhI(OAc) 2 in 1996. Since 2004, Sanford et al [2][3][4][5][6][7][8][9][10] and others [11][12][13][14] have pioneered practical, directed C-H activation for C-O and C-C bond formation reactions that also employed Pd(OAc) 2 as the catalyst.…”