Total synthesis of madindoline A

Abstract

The total synthesis of madindolin A was achieved. Stereoselective construction of the quaternary carbon in the cyclopentenedione moiety was accomplished by alkylation of dienolate bearing a chiral auxiliary. The coupling of sterically hindered aldehyde 17 and acid-sensitive amine 30 was achieved by developing a new reductive amination method using Sn(OTf)2 and NaBH(OAc)3. After the reductive coupling, the cyclopentenedione skeleton of madindoline was constructed by intramolecular condensation of triketone 5.