Enantioselective Total Synthesis of Cepharatines <i>via</i> Bioinspired Ring Reconstruction
Minami Odagi, Taisei Matoba, Kazuo Nagasawa
Abstract
We describe enantioselective total syntheses of cepharatines A-D, members of the hasubanan alkaloid family, which feature an unusual tetracyclic skeleton including an azabicyclo[3.3.1]nonane motif. A key reaction is a regio-divergent oxidative phenolic coupling reaction that affords the tricyclic core structure of hasubanan with different substitution patterns on the A-ring, including the all-carbon quaternary stereogenic center at C13, in a single step. The characteristic tetracyclic azabicyclo[3.3.1]nonane motif was constructed by means of a bioinspired cascade reaction involving the retro-aza-Michael reaction/hemiaminal formation.
Topics & Concepts
StereocenterChemistryEnantioselective synthesisNonaneStereochemistryHemiaminalTotal synthesisStructural motifRing (chemistry)Quaternary carbonCascade reactionOrganic chemistryCatalysisBiochemistryTraditional and Medicinal Uses of AnnonaceaeAdvanced Synthetic Organic ChemistryChemical synthesis and alkaloids