Chiral Tetrafluorobenzobarrelene Ligands for the Rhodium-Catalyzed Asymmetric Cycloisomerization of Oxygen- and Nitrogen-Bridged 1,6-Enynes


  • This work has been supported by a Grant-in-Aid for Scientific Research (S) (19105002) from the MEXT (Japan).


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The long and winding Rhoad: The asymmetric cycloisomerization of nitrogen- and oxygen-bridged 1,6-enynes proceeded in the presence of a cationic rhodium complex that was coordinated by PPh3 and a chiral diene ligand to afford high yields of chiral 3-aza- and 3-oxabicyclo[4.1.0]heptenes and high enantioselectivities. TS=4-toluenesulfonyl, Tf=trifluoromethanesulfonyl.