Ring-Closing Metathesis of Acrylates: A Comparative Study

The efficiency of ring-closing metathesis (RCM) reactions of various acrylates to form 2 (5 H)-furanones, catalyzed by second-generation ruthenium complexes, is investigated in detail. In particular the effects of substrate concentration and substrate structure were studied for indenylidene and benzylidene catalysts, both of which are shown to catalyze the RCM reaction in good yields. The starting substrate concentration is shown to be an important factor in the reaction, as, at excessive initial substrate concentrations, irreversible catalyst deactivation seems to occur, whereas high catalyst loadings appear to be unnecessary.