Tb(OTf)₃‐Catalyzed Asymmetric Nazarov Reaction of Triaryldivinyl Ketones

Different rare‐earth salts can regulate asymmetric 6 π or 4 π cyclization of triaryldivinyl ketones at different temperatures. The asymmetric Nazarov reaction of triaryldivinyl ketones is realized under the catalysis of Tb(OTf) 3 ‐Pybox complex in tetrachloroethene at relatively high temperature, affording methyl (1 R ,5 S )‐3,4,5‐triaryl‐2‐oxocyclopent‐3‐ene‐1‐carboxylates in moderate to good yields with good to excellent enantioselectivities in most cases. The π ‐stacking interaction between substrates and the phenyl group of the best ligand plays an important role in determining the enantioselectivity. Both solvent and reaction temperature tune the periselectivity. Relatively high temperature favors the Nazarov reaction. The rare‐earth ions also execute an important impact in controlling asymmetric pericyclic reactions of triaryldivinyl ketones.