The assignment of diastereotopic menthyl groups by two-dimensional NMR

The ¹³C and ¹H NMR spectra of (–)-bis1R, 3 R, 4S]menthylphosphine (1) are assigned by two-dimensional double quantum NMR and ¹³C? ¹H shift correlation diagrams. The variable temperature spectra of 1 indicate hindered rotation about the P? C bonds.