I have a problem with MnO2 oxidation of ferrocenophane (alpha-aromatic) alpha-position. I think MnO2 is the best reagent for this purpose (it worked excellent on my old lab) but now I can`t repeat previous result. I don`t feel sure of quality of my MnO2. I make my oxidation at ambient temperature in dry benzene. I tried to sonicated it but it did not work well. After addition of few drops of acetic acid I obtain desired product in moderate yield in the mixture with another compounds (acetic derivative and alcohol I guess). Please, if you know some similar convenient method for the activation of Mon2, answer me. It could help me very much. Thank you.