Novel Catalysis by N-Hydroxyphthalimide in the Oxidation of Organic Substrates by Molecular Oxygen

Aerobic Oxidation of Cyclohexane using N‐Hydroxyphthalimide Bearing Fluoroalkyl Chains

“…By the addition of ZrA C H T U N G T R E N N U N G (acac) 4 (10 mmol) to the 2 system, 1 was converted to 2 (856%), 3 (794%), and 4 (12%) after 6 h and to 2 (1796%), 3 (1962%), and 4 (48%) after 14 h, and the TONs of the NHPI oxidation of 1 were increased from 10.9 at 6 h and 19.0 at 14 h in the absence of Zr-A C H T U N G T R E N N U N G (acac) 4 to 16.6 at 6 h and 38.1 at 14 h in the presence of ZrA C H T U N G T R E N N U N G (acac) 4 , respectively (entries 1 and 2). Similarly, the TONs of F 15 -NHPI after adding ZrA C H T U N G T R E N N U N G (acac) 4 were increased from 20.3 to 35.7 at 6 h and from 37.8 to 49.2 at 14 h (entries 3 and 4).…”

“…The aerobic oxidation of cyclohexane (1) is a very important industrial process for the production of primary and specialty chemicals like cyclohexanol (2), cyclohexanone (3), and adipic acid (4). [1] Nowadays, the aerobic oxidation of 1 leading to a mixture of 2 and 3 which is generally referred to as K/A oil is usually carried out under the influence of a small amount of cobalt salts.…”

“…[3] By the use of our catalytic system, cycloalkanes can be oxidized in acetic acid even at 100 8C to give oxygenated products like alcohols, ketones and dicarboxylic acids in higher conversions. [4] However, the NHPI-catalyzed aerobic oxidation of cycloalkanes like 1 without a solvent was difficult to perform in higher conversion because of the slight solubility of NHPI bearing a hydroxyimide (> N-OH) group in hydrophobic media like cycloalkane 1. Thus, we prepared lipophilic NHPI derivatives having long alkyl chains which are easily dissolved in hydrocarbons like 1, and the aerobic oxidation of 1 without a solvent by these lipophilic NHPI catalysts was found to give cyclohexanol 2 and cyclohexanone 3 along with a small amount of adipic acid 4 in higher conversion compared with the oxidation by NHPI.…”

N ‐Hydroxyphthalimide (NHPI)‐Organocatalyzed Aerobic Oxidations: Advantages, Limits, and Industrial Perspectives

“…However, PINO production in the reaction medium was not experimentally proven until 1995 when, thanks to the pioneering work of Ishii et al, a triplet signal, originating from PINO, was detected by Electron Spin Resonance (ESR) technique, after exposing NHPI to molecular oxygen [3]. With this work, regarding the oxidation of alkanes and alcohols, Ishii initiated the relatively recent history of oxidations catalyzed by NHPI.…”

Efficient Oxidation of Adamantanes by Sodium Nitrite with Molecular Oxygen in Trifluoroacetic Acid

“…The second one was an oxygen effect. The reactions in Entries 1-7 were carried out under an oxygen atmosphere (1 atm) or an aerobic condition where satisfactory results were obtained when NaNO 2 was used as a catalyst (Entries [2][3][4][5]8). However, the yield of 3a was narrowly 10% under a nitrogen atmosphere even if 0.2 equiv of NaNO 2 was used (Entry 9).…”