Copper Complex of Pinene based Schiff base [CuSBADBH]2: Synthesis and its Application in Catalytic Asymmetric Nitroaldol (Henry) Reaction

Abstract

AbstractEight new pinene based tridentate Schiff bases of (+)‐(1S,2R,3S,5S)‐3‐amino‐6,6‐dimethylbicyclo[3.1.1]heptan‐2‐ol were synthesized from (+)‐(α)‐pinene. Copper complexes of these Schiff bases were prepared for asymmetric nitroaldol (Henry) reaction. Among the eight copper complexes, 3‐methylsalicylaldehyde‐derived [CuSBADBH‐4]2 32 showed high chiral induction (85 % ee) for the catalytic asymmetric Henry reaction of 4‐nitrobenzaldehyde. Under optimal reaction conditions, 1 mol% [CuSBADBH‐4]2 32 catalyzed enantioselective Henry reaction of various aromatic and poly aromatic aldehydes afforded the corresponding (R)‐β‐hydroxy nitroalkanes with high ee (up to 92 %) and yield (up to 99 %).