Application of modified Mosher's method for primary alcohols with a methyl group at C2 position

The absolute configurations of a series of primary alcohols possessing a branched methyl group at C2 position were examined on the basis of a modified Mosher's method proposed by Minale et al. It was revealed that in many cases the absolute configurations at C2 were assignable from the chemical shift differences of geminal protons of the methylene attached to the ester linkage in the alpha-methoxy-alpha-trifluoromethylphenylacetyl (MTPA) derivatives. The scope and limitation of this method are described.