Conformation and absolute configuration of (1S,2S)-2-(phenyl-selan-yl)cyclo-hexyl (R)-2-meth-oxy-2-(1-naphth-yl)propionate.

The relative and absolute configurations of the title compound, C(26)H(28)O(3)Se, were assigned from the known configuration of (R)-(-)-2-meth-oxy-2-(1-naphth-yl)propionic acid used as starting material, and by examination of the Bijvoet (Friedel) pairs, using the anomalous dispersion data collected with Mo Kα radiation at low temperature. The geometry around the carbonyl group exists in the syn conformation, as reflected in torsion angles involving this group, and the stability of the structure is affected by weak bifurcated intra-molecular C-H⋯O hydrogen bonds.