Haoran Zhang, Fangyan Liu, Quan Qian, Rui Wu, Shifa Zhu
A dirhodium-catalyzed diastereoselective cycloisomerization of enynes derived from cyclohexadienone-tethered ynals is described. This reaction enables a concise synthetic pathway toward a library of 6-6-5 fused tricyclic frameworks incorporating three consecutive stereogenic centers. This protocol features excellent diastereoselectivities. Mechanistic studies indicate a dirhodium carbene is possibly involved. Trapping this species with external alkenes furnishes structurally intricate fused/spirocyclic adducts bearing five stereocenters with complete diastereoselectivity.