In-Situ Monitoring of Enantiomeric Excess During a Catalytic Kinetic Resolution

Abstract

Vibrational Circular Dichroism combined with FTIR spectroscopy (VCD-IR) is demonstrated as a viable tool for the in situ measurement of enantiomeric excess during asymmetric catalytic transformations. Employing the Jacobsen (salen)Co-catalyzed hydrolytic kinetic resolution of racemic epoxides as a proof-of-concept case study, methodology is developed to monitor the enantiomeric excess of the epoxide substrate as a function of conversion of the limiting reactant, water. Comparison of results for monomeric and oligomeric catalysts probes the molecularity of the catalyst by investigating nonlinear effects in catalyst enantiopurity. These results are in excellent agreement with previous mechanistic investigations of this reaction based on kinetic measurements and computational studies.