AmericanChemicalSociety.com

Over the past 12 months, we have worked to understand the role of catalyst-substrate interactions at the transition state for the Corey-Bakshi-Shibata (CBS) reduction.  We have completed 13C and 2H kinetic isotope effect measurements at each carbon position and each methyl group, respectively, in 2',5'-dimethylisobutyrophenone.  These measurements have yielded surprising implications for the mechanism of stereocontrol in the CBS reduction.  We have found that both the boroalkyl group and the stoichiometric reductant place steric demands upon the favored transition state.  It is the balance of these demands which dictate stereoselection.  In addition to the three manuscripts which we have published on this work, we have another that is nearing submission.