Synthesis and biological evaluation of the four racemic stereoisomers of the structure proposed for sorgolactone, the germination stimulant from Sorghum bicolor

Article abstract of DOI:10.1016/S0040-4039(97)00379-1

The synthesis of the racemates of the structure 1 proposed for sorgolactone and its three stereoisomers was achieved by confirming the stereostructures of the intermediate (±)-6 and the final product (±)-1 by X-ray analyses. Biological evaluation of the products employing clover broomrape (Orobanche minor) seeds revealed that the order of activity as a germination stimulant was (±)-strigol ~ (±)-9 ≤ (±)-12 > (±)-1 > (±)-11.