Abstract To obtain further evidence for the importance of the ground state conformational and orbital properties in π-facial diastereoselection of 1, 3-diheteran-5-ones (heteroatom= O, S, Se), 2-phenyl-1, 3-diselenan-5-one (3a) has been synthesized, and its π-facial diastereoselection upon hydride reduction has been examined. The experimental data of π- facial stereoselection of 3a has been successfully rationalized by the exterior frontier ...
