Total Synthesis of (+)-Haperforin G

(+)-Haperforin G was synthesizedin 20 steps from commerciallyavailable starting materials. A Co-catalyzed intramolecular Pauson-Khandreaction was used for stereoselective construction of cyclopentanonebearing an all-carbon quaternary stereogenic center at the bridge-headposition. Light-initiated photocatalysis was used for convergent andasymmetric cross-coupling of the unstabilized C(sp(3)) radicalwith an enone. The developed chemistry paves the way to the synthesisof structurally diverse analogs of haperforin G (6).