SYNTHESIS OF -ETHYL-1,5-DIMETHYL-6,8-DIOXABICYCLO[3.2.1]OCTANE, THE AGGREGATION PHEROMONE OF MALE BEECH BARK BEETLES, TAPHRORYCHUS BICOLOR (COL, SCOL)

The absolute configuration of the new bicyclic acetal 2-ethyl-1,5-dime thyl-6,8-dioxabicyclo[3.2.1]octane (1), identified as an aggregation p heromone of males of the beech bark beetle, Taphrorychus bicolor, was determined by unambiguous synthesis and NMR experiments. The syntheses of the racemates of both diastereomers and of optically pure samples are described. The natural product proved to show (1S,2R,5R) configura tion.