Total Synthesis of Spiroalkaloids Lycibarbarines A–C

Abstract The concise and efficient synthesis of tetrahydroquinoline alkaloids lycibarbarines A−C has been accomplished in four steps from a common intermediate derived from commercially available 2‐deoxy‐ D ‐ribose and 8‐hydroxyquinoline. For the synthesis of the unique tetracyclic spiro‐heterocycle skeleton we employed a synthetic strategy that features two key transformations: iodomethyllithium‐based homologation of lactone / N‐alkylation to access tetracyclic spiro‐heterocycle skeleton in one step and one‐pot acetonide deprotection, hemiacetal formation, and spirocyclization cascade process.