In Situ Monitoring of Asymmetric Transfer Hydrogenation of Imines Using NMR Spectrometry
Keywords:
asymmetric transfer hydrogenation, Noyori, enantioselectivity, chiral solvationAbstract
Three methods for determination of enantioselectivity of asymmetric transfer hydrogenation of imines are presented: direct NMR observation of diastereomeric reduction products of a chiral imine, chiral solvation with Pirkle’s alcohol, (-)-(1R)-1-(9-anthryl)-2,2,2-trifluoroethan-1-ol and precolumn derivatization with (-)-(1R)-menthyl chloroformate followed by GC analysis on a non-chiral column of the resulting diastereomeric carbamates.