Polymer-Supported Non-Chiral and Homochiral Schrock Catalysts

Significance

Immobilization of both non-chiral and homochiral Schrock catalysts via the aryl­imido ligand was accomplished for the first time. Thus, a non-chiral Schrock catalyst 1, and homochiral catalysts 2 and 3 were prepared from 4-bromo-2,6-dimethylaniline (for 1 and 2) or 4-bromo-2,6-diisopropylaniline (for 3) with linear polystyrene (M_n = 10,000; PDI = 1.5) in eight steps. The ring-closing metathesis (RCM) and ring-opening cross-metathesis were performed with 1 (0.1-1 mol% Mo) in CH₂Cl₂ or CDCl₃ to give the corresponding products in 64-100% yield (4 examples). The catalyst 2 or 3 (5 mol% Mo) was subjected to the enantioselective RCM to afford the corresponding products in 43-99% conversion with 6-95% ee (7 examples).