The Oxidation of Anisole and Diphenyl Ether with Trifluoroperoxyacetic Acid

Chemo‐ and Regioselective Direct Hydroxylation of Arenes with Hydrogen Peroxide Catalyzed by a Divanadium‐Substituted Phosphotungstate

“…Notably, the para ‐hydroxylation of 1 a preferentially proceeded, and the ortho ‐/ meta ‐/ para ‐ 2 a ratio was 3:<1:96. The present regioselectivity (96 %) for para ‐ 2 a was much higher than those reported for stoichiometric reagents, such as peroxytrifluoroacetic acid (21 %)9a and hydroxyl radical (10 %),9b or H 2 O 2 based catalytic systems, such as sterically hindered metalloporphyrins (23–90 %),2c, 10a TS‐1 (a titanium silicate zeolite; 71–75 %),2a [Fe(tpaa)(ClO 4 ) 2 ] (tpaa=tris‐[ N ‐(2‐pyridylmethyl)‐2‐aminoethyl]amine; 51 %),10b [(dppe)Pt(CF 3 )(CH 3 )(CH 2 Cl 2 )](ClO 4 ) (dppe=1,2‐bis(diphenylphosphino)ethane; 15 %),2h and K 7 NiV 13 O 38 ⋅16 H 2 O (0 %; Table S2) 2i. Hydroxylation efficiently proceeded even at 298 K without significant changes in catalytic performance.…”

Tuning the Reactivity of Peroxo Anhydrides for Aromatic C–H Bond Oxidation

“…We therefore decided to use PFB (method A) as the solvent of choice and proceeded with further optimization of the reaction conditions (Table , entries 7–10). Overall, the best results for anisole ( 5a ) oxidation using peroxide P4 were slightly superior (65%, 1:2 ortho / para ) to those reported for malonoyl (63%, 1:1.6) and phthaloyl peroxide (45%, 1.4:1, with opposite regioselectivity) and that with trifluoroperoxyacetic acid (34%, 3.6:1), both in terms of yield and regioselectivity.…”

“…Pale yellow solid. 1 H NMR (400 MHz, CDCl 3 ): δ = 7.01 (dd, J = 7.8, 1.9 Hz, 1H), 6.56 (dd, J = 7.8, 1.9 Hz, 1H), 6.45 (dd, J = 7.8, 1.9 Hz, 1H), 6.42−6.36 (m, 2H), 6 79 Procedure for the Synthesis of Dihydroxy[2.2]paracyclophanes (6p2 and 6p3). [2.2]Paracyclophane (0.21, 1 mmol) was placed inside a 25 mL flask equipped with a magnetic stirrer bar.…”

“…Common strategies for preparation of phenols include use of hydrogen peroxide in combination with strong acids, organic peroxy acids, and organic peroxides (Scheme ). − However, the applicability of such methods remains limited due to harsh reaction conditions, lack of selectivity, and frequently poor yields. It is striking that even with the advancement of metal catalysis for arene oxidation, the regioselective hydroxylation of aromatic compounds remains one of the most challenging chemical transformations.…”

Superacid‐Catalyzed Reactions

“…[606][607][608][609][610][611][612][613][614][615] Although moderate-to-good yields of phenols, based on the amount of hydrogen peroxide used, were reported for the AlCl 3catalyzed reaction of simple aromatics with hydrogen peroxide, a 10-fold excess of aromatics was used over hydrogen peroxide. [606][607][608][609][610][611][612][613][614][615] Although moderate-to-good yields of phenols, based on the amount of hydrogen peroxide used, were reported for the AlCl 3catalyzed reaction of simple aromatics with hydrogen peroxide, a 10-fold excess of aromatics was used over hydrogen peroxide.…”