<jats:title>Abstract</jats:title><jats:p>Three novel alkaloids, macropodumines A–C (<jats:bold>1</jats:bold>–<jats:bold>3</jats:bold>), were isolated from the stem of <jats:italic>Daphniphyllum macropodum</jats:italic> Miq. Interestingly, the structure of macropodumine A (<jats:bold>1</jats:bold>) was characterized as having a fused pentacyclic system including an unusual eleven‐membered macrolactone ring, whereas macropodumine B (<jats:bold>2</jats:bold>) contains a rare cyclopentadienyl carbanion, which is stabilized as a zwitterion by an internal iminium cation. The structures of these new metabolites were established on the basis of their detailed spectroscopic analysis. In particular, the unique structure of zwitterion <jats:bold>2</jats:bold> was further confirmed by using single‐crystal X‐ray diffraction analysis.