Abstract
A novel class of catalysts for aerobic oxidation for a wide variety of organic substrates was developed. Benzylic compounds such as fluorene were oxidized with molecular oxygen in the presence of N-hydroxyphthalimide (NHPI) to give the corresponding oxygenated products such as fluorenone. For the oxidation of cycloalkanes, polycyclic alkanes and alkylbenzenes, which are difficult to be oxidized by NHPI alone, a combined catalytic system of NHPI with Co(acac) n ( n = 2 or 3) was found to be efficient for the oxidation of these substrates. Thus cycloalkanes were successfully oxidized with dioxygen in the presence of a catalytic amount of NHPI (10 mol%) and Co(acac) 2 (0.5 mol%) in acetic acid at 100°C to give cycloalkanones and dicarboxylic acids as principal products. Alkylbenzenes were also oxidized by this catalytic system to form the corresponding carboxylic acids and/or carbonyl compounds in good yields. Exposure of NHPI to atmospheric oxygen in benzonitrile at 80°C generated phthalimide N-oxyl (PINO), a key intermediate, in this oxidation. The formation of PINO from the NHPI and dioxygen was significantly accelerated by adding Co(acac) 2 to the reaction system.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.