Total Synthesis of Farnesin through an Excited‐State Nazarov Reaction
Yonglei Que, Hao Shao, Haibing He, Shuanhu Gao
Abstract
Abstract The asymmetric total synthesis of farnesin, a rearranged ent ‐kaurenoid, was achieved through a convergent approach involving photo‐Nazarov and intramolecular aldol cyclizations to build the syn‐syn‐syn hydrofluorenol ABC ring system and bicyclo[3.2.1]octane CD ring system in the first application of a UV‐light‐induced excited‐state Nazarov cyclization of a non‐aromatic dicyclic divinyl ketone in a total synthesis. Unlike the conventional acid‐promoted ground‐state Nazarov reaction, the excited‐state Nazarov reaction enables stereospecific formation of the highly strained syn‐syn‐syn ‐fused hydrofluorenone scaffold through a disrotatory cyclization.
Topics & Concepts
Conrotatory and disrotatoryChemistryTotal synthesisRing (chemistry)OctaneExcited stateKetoneAldol reactionIntramolecular forceAldol condensationBicyclic moleculeStereospecificityStereochemistryPhotochemistryCombinatorial chemistryOrganic chemistryCatalysisNuclear physicsPhysicsOxidative Organic Chemistry ReactionsBioactive Natural Diterpenoids ResearchMarine Sponges and Natural Products