DETERMINATION OF THE ABSOLUTE-CONFIGURATION OF CHIRAL SECONDARY ALCOHOLS - NEW ADVANCES USING C-13-NMR AND 2D-NMR SPECTROSCOPY

The use of H-1-C-13 and H-1-H-1 2D COSY correlation experiments substantially enhances the potential of the NMR procedure for determining the absolute configuration of chiral secondary alcohols via their diastereomeric MPA and/or MTPA esters. Phenyl ring current effects are observed over remarkably long distances and comparable effects are seen for both C-13 and H-1 chemical shifts. The use of C-13 chemical shifts to aid configurational assignment is particularly valuable.