The Enantioselective Synthesis of Chiral Carbocyclic Nucleosides via Palladium-Catalyzed Asymmetric Allylic Amination of Alicyclic MBH Adducts with Purines

The enantioselective synthesis of carbocyclic nucleosides through the palladium-catalyzed asymmetric allylic amination of alicyclic Morita-Baylis-Hillman (MBH) adducts with purines was successfully developed. With a combination of Pd-2 (dba)(3)/L7 as catalyst, various optically active carbocyclic nucleosides featuring a C=C double bond in the carbocycle moiety were obtained in high yields (up to 97%) with excellent N-9/N-7-selectivities (> 95/5) and enantioselectivities (up to > 99.6%). In addition, these nucleoside analogs allowed for rapid transformation to a variety of other interesting structurally diverse chiral carbocyclic nucleosides.