(Faculty of Pharmaceutical Sciences, Osaka University, 133-1 Yamada-Kami, Suita, Osaka 565, Japan) ... Summary (f)-Solavetivone (1) was synthesized by a new spiro-annelation reaction and a unique regio- and stereo- selective reduction of the spiro-dienone (4) to give (5), the structure of which has been determined by X-ray crystal- lography. ... ( -)-SOLAVETIVONE (1), which has a vetispirane skeleton, has been isolated as a stress metabolite from potato tubers ...