Total synthesis of aspidophytine

A total synthesis of aspidophytine was accomplished by employing a newly developed strategy for the enantiospecific syntheses of aspidosperma alkaloids. The key steps involve a novel ketene-lactonization reaction of a chiral vinyl sulfoxide (Marino annulation reaction) to set up the chiral quaternary carbon center, and a tandem Michael addition-alkylation reaction sequence to form the polycyclic core structure.