Total Synthesis of Neuroprotective Agents, (+)-Lycibarbarine A and (-)-Lycibarbarine B

Wedescribe the convergent total syntheses of lycibarbarines Aand B which are potent neuroprotective agents recently isolated fromthe fruits of Lycium barbarum. The synthesis highlightsthe construction of a unique spiro oxazine heterocyclic motif imbeddedin these natural products. The synthesis is accomplished from thecommercially available 8-hydroxyquinaline and 2-deoxy-d-riboseas key starting materials. The synthesis features a Reimer-Tiemannreaction, selective amine alkylation with a keto tosylate derivative,and spiroketalization to form an oxazine core.

Automated summary

We present the convergent total syntheses of lycibarbarines A and B, which are recently discovered potent neuroprotective agents derived from Lycium barbarum fruits. The syntheses showcase the construction of a unique spiro oxazine heterocyclic motif found in these natural products. Key starting materials used in the synthesis include commercially available 8-hydroxyquinaline and 2-deoxy-D-ribose, and the synthesis involves Reimer-Tiemann reaction, selective amine alkylation with a keto tosylate derivative, and spiroketalization to form an oxazine core.