Wednesday, June 25, 2008
Congressional Room (Capital Hilton)

A New Method for Oxidation of Benzylic Alcohols Using MgBr2/UHP in Ionic Liquid

Hee Joong Park and Jong Chan Lee. Chung-Ang University, Seoul, South Korea

The transformation of benzylic alcohols to carbonyl compounds is one of the most fundamental reactions in organic synthesis. Various methods have been developed for the oxidation of benzylic alcohols to the corresponding benzaldehydes or ketones. However, the majority of known methods commonly have one or more disadvantages such as difficulty in manipulation, long reaction times and utilization of toxic reagents. Therefore, it is still desirable to develop a new efficient oxidant with properties of high stability and low toxicity ready availability for the benzylic oxidations. In recent years, ionic liquids have been acknowledged as green alternatives to the toxic and volatile organic solvents for various chemical reactions. The urea hydrogen peroxide complex[CO(NH2)2H2O2, UHP] considered as oxidation reagents of choice due to its safe and environmentally friendly nature. In recent years, UHP has proved to be effective in solid state reactions, both under heating or microwave irradiation, so becoming an interesting eco-friendly reagent. Effective oxidation reactions of primary and secondary benzlyic alcohols into the corresponding benzaldehydes or ketones have been accomplished using magnesium bromide(MgBr2) and urea hydrogen peroxide(UHP) in [bmim]BF4 ionic liquid.