Enantioselective Ring Opening of meso‐Epoxides with Silicon Tetrachloride Catalyzed by Pyridine N‐Oxides Fused with the Bicyclo[3.3.1]nonane Framework

摘要: The synthesis of new chiral Lewis basic organocatalysts that contain pyridine N-oxide moieties fused with the bicyclo[3.3.1]nonane framework is reported. obtained N-oxides were employed as catalysts in enantioselective ring opening meso-epoxides silicon tetrachloride. Derivative 1b endowed two 2,4-diaryl-substituted proved to be a particularly effective catalyst for desymmetrization norbornene oxide 16i furnish Wagner–Meerwein rearrangement product 20i unprecedented 96 % ee. Difunctional congener 3, which striped 4-aryl substituents, exhibited moderate high levels asymmetric induction (47–88 % ee) alicyclic epoxide substrates.