Benzil and its derivatives naphthil and pyridil have been found to undergo a dianionic oxy-Cope rearrangement upon reaction with 2-lithio-4,5-dihydrofuran to give 3,3'-octahydrobifuranyls selectively as the meso diastereomers. The diastereoselectivity is explained based on the reaction mechanism and the conformation of the starting material. 4,4'-Di-tertbutylbenzil gave the respective intramolecular aldol adduct, whose relative configuration was determined by NOE experiments. [ABSTRACT FROM AUTHOR]