(6R)-2-tert-Butyl-6-[(4R,5S)-3-isopropyl-4-methyl-5-phenyl-oxazolidin-2-yl]phenol.

In the title compound, C(23)H(31)NO(2), the lone pair on the nitro-gen atom is oriented to facilitate intra-molecular hydrogen bonding with the hydr-oxy group residing on the phenyl substituent. The five-membered ring adopts an envelope confornmation with the O atom at the flap. The absolute stereochemistry was verified by measurement of optical activity using a digital polarimeter.

(6S)-2,4-Di-tert-butyl-6-[(4S,5R)-3-iso-propyl-4-methyl-5-phenyloxazolidin-2-yl]phenol.

The title oxazolidine compound, C(27)H(39)NO(2), was synthesized from N-isopropyl-norephedrine. The dihedral angle between the aromatic rings is 70.33 (5)°. The N atom of the heterocycle is oriented to allow intra-molecular O-H⋯N hydrogen bonding with the hydr-oxy substituent.

(6S)-2-tert-Butyl-6-[(4S,5R)-3,4-dimethyl-5-phenyloxazolidin-2-yl]phenol.

The title compound, C(21)H(27)NO(2), exhibits hydrogen bonding between the phenolic H atom and the heterocyclic N atom. The absolute configuration of the mol-ecule is known from the synthetic procedure.