Surprisingly, during asymmetric reduction of my benzylic ketone (prochiral ) by Itsuno corey reduction, the vinylic (ortho positon)protons are disappearing as per the NMR spectra. This would normally imply hydroboration, but I am not using any NaOH/H2O2 to quench my reaction mixture, and using MeOH instead.
Any ideas on what might be going on here?