Total Synthesis and Structure–Activity Relationship Studies of Phelligridins C and D, and Phellifuropyranone A

Abstract α-Pyrone polyphenols, phelligridins C and D (meshimakobnols B and A), and phellifuropyranone A, isolated from a Japanese mushroom, are growth inhibitors of cancer cells. Herein, we report full details of the total synthesis of phelligridins C and D. The key reactions of the synthetic pathways were Pd catalyzed cross-coupling and aldol-type condensation. This strategy also enabled the total synthesis of phellifuropyranone A and artificial analogs of phelligridins. Subsequent biological evaluation of these compounds clarified that the whole skeleton of phelligridin C and the catechol group of the left hand side are essential for the cytotoxicity.