Total synthesis of (.+-.)-solavetivone and aglycone A3. Regio- and stereo-selective Birch reduction of 6,10-dimethyl-2-hydroxy-spiro[4.5]deca-6,9-dien-8-one.
(±)-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.