Total synthesis of (+)-grindelic acid by stereocontrolled oxonium ion activated pinacol ring expansion. Chemical proof of the absolute configuration of all grindelane diterpenes

Article abstract of DOI:10.1016/0040-4039(95)01187-M

(+)-Grindelic acid, synthesized enantioselectively from the levorotatory Wieland-Miescher ketone and (-)-linalool and necessarily formulated as 1a, is shown to be antipodal to the major diterpenoid of Grindelia species.