ENANTIOSPECIFIC SYNTHESIS OF (-TRACHELANTHIC AND (-)-TRACHELANTHIC ACIDS VIA ASYMMETRIC DIHYDROXYLATION AND THEIR CONVERSION TO THE PYRROLIZIDINE ALKALOIDS INDICINE AND INTERMEDINE())

Asymmetric dihydroxylation of (E)-ethyl 2-isopropylbut-2-enoate with A D-mix-alpha and AD-mix-beta, followed by saponification, gives (-)- an d (+)-trachelanthic acids, respectively, which are each coupled via th eir acetonides with (+)-retronecine to yield the pyrrolizidine alkaloi ds indicine and intermedine.