抄録
Lineatin is an attractant compound isolated from frass produced by female beetle of Trypodendron lineatum(Olivier) boring in Douglas fir. (±)-3,3,7-Trimethyl-2,9-dioxatricyclo[4.2.1.0^<4,7>] nonane 1 and (±)-3,3,7-trimethyl-2,9-dioxatricyclo[3.3.1.0^<4,7>] nonane 2 were synthesized to confirm one or the other of the proposed structures. The key step in the present synthesis was the (2+2) photocycloaddition of vinyl acetate to a cyclopentenone 4. The latter 2 was shown to be (±)-lineatin, the ambrosia beetle pheromone. In order to determine the absolute stereochemistry of the natural pheromone, the both enantiomers of lineatin were also synthesized by another stereo-controlled method. From the CD spectra of both enantiomers of the resolved key intermediate 20 and the ORD of the final product, the absolute configuration of (+)-lineatin was tentatively assigned to be 1S, 4R, 5S, 7S.
