(2R*, 3R*)-2-(2-phenoxyethyl)tetrahydrofuran-3-yl acetate: Single Crystal X-Ray Diffraction Analysis and Mechanistic Implications

Our laboratory recently explored a highly stereospecific rearrangement of epoxides into tetrahydrofurans. To unambiguously determine the stereochemical outcome of this rearrangement, single crystals of one of the products, (2R*, 3R*)-2-(2-phenoxyethyl)tetrahydrofuran-3-yl acetate, were grown and analyzed. Based on the crystal structure data, we were able to show that the contiguous stereocenters of this molecule are in a syn configuration, and we now suggest with confidence a plausible mechanism for the rearrangement reaction. The syn configuration of the ring may also account for the inability of most members of this class to crystallize, as it imparts a kink in the structure reminiscent of low-melting unsaturated fatty acids.