Residual dipolar couplings of freely rotating groups in small molecules. Stereochemical assignment and side-chain conformation of 8-phenylmenthol.

A procedure for the direct use of (1)D(CH) residual dipolar couplings (RDCs) from freely rotating groups in the structural analysis of small molecules was implemented. (1)D(CH) RDCs were used to determine both the preferred conformation and the stereochemical assignment of the diastereotopic geminal methyls of 8-phenylmenthol. Furthermore, a method was also set up to fit RDC data to a set of conformations in solution on the assumption that they all have the same alignment tensor.