Asymmetric Total Synthesis of (−)-Lemnalemnane A
Toyoharu Kobayashi, Rina Sugitate, Kyohei Uchida, Yuichiro Kawamoto, Hisanaka Ito
Abstract
The asymmetric total synthesis of lemnalemnane A, a rare rearranged sesquiterpenoid, has been accomplished in 13 steps from ( S )-carvone. The key features of the synthesis are the removal of the isopropenyl group derived from ( S )-carvone via a radical intermediate, the formation of the bicyclo[3.3.1]nonane skeleton using the Dieckmann condensation, the stereocontrolled construction of five continuous chiral centers by chemo- and stereoselective reduction and stereoselective introduction of the alkyne group, and the formation of the spirolactone moiety via a hemiacetal intermediate.
Topics & Concepts
ChemistryStereoselectivityTotal synthesisMoietyStereochemistryHemiacetalAlkyneCarvoneNonaneSynthonBicyclic moleculeOrganic chemistryCatalysisEssential oilLimoneneChromatographySynthetic Organic Chemistry MethodsAsymmetric Synthesis and CatalysisOxidative Organic Chemistry Reactions