A Cytotoxic Indole Characterized by Incorporation of a Unique Carbon–Nitrogen Skeleton and Two Pentacyclic Corynanthean Alkaloids Incorporating a Substituted Tetrahydrofuranone Rin... by Wong, Soon Kit, Wong, Suet Pick, Sim, Kae Shin, Lim, Siew Huah, Low, Yun Yee, Kam, Toh Seok