Synthesis of Tricyclo[4,3,1,01,5]decane Core of Plumisclerin A Using Pauson–Khand Annulation and SmI2-Mediated Radical Cyclization

An efficient synthesis of the tricyclo[4,3,1,01, 5]decane core (B/C/D rings) of plumisclerin A, a unique cytotoxic marine diterpenoid, is described. A Pauson–Khand reaction and a SmI2-mediated radical 1,4-conjugate addition successfully served as key reactions for construction of the fully functionalized 5,6-fused rings and the highly strained cyclobutanol moiety with correct relative stereochemistries, respectively.