Stereospecific synthesis of cis-verbenol

Abstract

SHORT COMMUNICATIONScis-Verbenol 1 is contained in the aggregation pheromones of bark beetles Ips and Dendroctonus. This compound was formerly prepared by the reduction of (1R,5R)-or (1S,5S)-verbenones with LiAlH 4 [1] or NaBH 4 [2], yet the yield did not exceed 50% because of the formation of the mixture of cisand trans-verbenols as well as saturated alcohols, verbenals. To avoid the 1,4-addition to the conjugated carbonyl group a system NaBH 4 -Ce(NO 3 ) 3 ·6H 2 O was applied [3]. The main drawbacks of these procedures were insufficiently low yields, not high enough regionand stereo-selectivity of hydride reagents and consequently the necessity to use recrystallization and preparative GC for isolation of the taget substance in the pure state.