Exo and endohormones. XX Synthesis of racemic 2-ethyl-1,6-dioxaspiro[4,4]nonane, the aggregation pheromone of Pityogenes chalcographus (Coleoptera, Scolytidae)

The synthesis of a diastereoisomeric mixture of 2-etyl-1,6-dioxaspiro[4,4]nonane (chalcograne) a main component of the aggregation pheromone of the spruce bark beetle Pityogenes chalcographus (Coleoptera, Scolytidae), a serious pest in European forests, by 1,7-nonanediol cyclization using Pb(OAc)(4) is given below. The side. products of spirocyclization were identified by GC/MS.