Abstract
Total syntheses of (-)-isoschizogamine and (-)-2-hydroxyisoschizogamine are described. The synthesis employs two asymmetric Michael additions to establish chiral centers at C7 and the quaternary carbon C20. Regioselective reduction of the methylthioiminium cation rather than the enamine generates an isoschizogamine-type pentacyclic skeleton. Acidic hydrolysis of the isoschizogamine-type intermediate in the absence of oxygen provides natural (-)-isoschizogamine. Conducting the reaction in the presence of oxygen leads to a multistep oxidative hydrolysis cascade that affords unnatural (-)-2-hydroxyisoschizogamine.
Full Text
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call