I have a question from my own synthesis, where I wanted to oxidize the position α to the indole into a ketone. It should be quite an easy reaction normally done by DDQ, but here I can only pot a hydroxy group on that carbon but not a carbonyl. I also tried to oxidize it further with Dess-Martin and IBX and failed. I have been wondering why this reaction is not working, but I couldn't find a clue... However if I oxidize the molecule without the pyrrole part (see attachment), the reaction worked without any problem. Could anybody provide some idea why these happen? Thanks very much!