Synthesis and stereochemical determination of an antifeeding bisabolanoid from Japanese cedar

The first enantioselective synthesis of (1S,3R,6R)-1-hydroxy-7(14),10-bisaboladien-4-one, a potent antifeedant isolated from the Japanese cedar, Cryptomeria japonica, was achieved starting from methyl (R)-4-hydroxy-3-methylbutanoate via a stereoselective carbonyl ene cyclization reaction as the key step. Comparison of the spectral data and specific rotation of the synthetic material with those of the natural product led to unambiguous stereochemical assignment of the antifeedant as 1S, 3R, and 6R.