Total Synthesis of Scandine

The total synthesis of scandine was achieved via three key transformations: an intramolecular reductive Heck reaction to construct the six-membered lactam, an intramolecular azomethine ylide cycloaddition to form the pyrrolidine and cyclopentane rings, and a ring-closing metathesis to generate an unsaturated six-membered ring. A cyclopropene ring served as an effective surrogate for the geminal divinyl group, while an alkyne unit introduced via alkynylation of a malonate derivative functioned as the reaction site for the pivotal ring-forming steps.