Kuroshine 类生物碱的合成研究

Kuroshine alkaloids are highly oxidized marine natural products isolated from Zoanthus, which have complex and diverse structure, including three all carbon quaternary carbon centers (C-9, C-12, and C-22), densely functional groups, and a highly oxidized skeleton. The main syntheic challenges include the construction of the fully hydrogenated phenanthrene A-B-C ring, the construction of adjacent quaternary carbon centers (C-9, C-22), and the precise introduction of oxidation states at C-11, C-28, and C-25 positions. A synthetic study on kuroshine alkaloids was conducted, successfully introducing the C-25 oxidation state through the addition of chloromethyl lithium to enone and epoxide rearrangement, and constructing adjacent quaternary carbon centers (C-9, C-22) through intramolecular alkylation substitution reactions. The C-12 oxidation state was introduced through a single electron epoxide opening mediated by samarium iodide. The synthesis of bicyclic aldehyde fragment 19 and chiral iodo fragment 20 was finally completed.