Construction of All-Carbon Quaternary Stereocenters via Asymmetric Cyclopropanations: Synthesis of Chiral Carbocyclic Pyrimidine Nucleosides

摘要

An efficient route to synthesize chiral carbocyclic pyrimidine nucleoside analogues containing all-carbon quaternary stereocenters has been established via the asymmetric intermolecular cyclopropanation of N1-vinylpyrimidines and -aryl diazoesters. With 2mol% of chiral dirhodium (II) carboxylate complex as the catalyst, a variety of chiral carbocyclic cytosine or uracil nucleoside analogues were obtained in good yields (up to 96% yield), high diastereoselectivities (20:1 dr), and excellent enantioselectivities (up to 99% ee).