Catalytic Asymmetric Polycyclization of Tertiary Enamides with Silyl Enol Ethers: Total Synthesis of (−)-Cephalocyclidin A
Qing‐Bo Zhuang, Jin-Rui Tian, Ka Lu, Xiao‐Ming Zhang, Fu‐Min Zhang, Yong‐Qiang Tu, Rong Fan, Zhihao Li, Yudong Zhang
Abstract
A catalytic enantioselective polycyclization of tertiary enamides with terminal silyl enol ethers has been developed by virtue of Cu(OTf) 2 catalysis with a novel spiropyrroline-derived oxazole (SPDO) ligand. This tandem reaction offers an effective approach to assemble bicyclic and tricyclic N -heterocycles bearing both aza - and oxa -quaternary stereogenic centers, which are primal subunits in a range of natural alkaloids. Strategic application of this methodology and a late-stage radical cyclization as key steps have been showcased in the concise total synthesis of (−)-cephalocyclidin A.
Topics & Concepts
ChemistryStereocenterEnolEnantioselective synthesisSilylationTotal synthesisOxazoleStereochemistryCatalysisBicyclic moleculeCombinatorial chemistryOrganic chemistryAdvanced Synthetic Organic ChemistrySynthetic Organic Chemistry MethodsBiological Activity of Diterpenoids and Biflavonoids