Ruthenium-Catalyzed Hydrogenation of Doubly Functionalized Polar Polynorbornenes and the Effect of Substituents in the Ester Groups

摘要

Ring-opening metathesis polymerization (ROMP) has been attracted great attention of homogeneous catalysis emerging over the last two decades,with important implications in synthetic organic and polymer chemistry as well as material chemistry.One of the most successful catalysts among these is the Grubbs' ruthenium catalysts,(PCy3)2Cl2Ru=CHPh (1) and (H2IMes)(PCy3)Cl2Ru=CHPh (2) (H2IMes = N,N-bis(mesityl) 4,5-dihydroimidazol-2-ylidene).Compared to polymers having aromatic rings in the main chain,one can expect that the cycloolefin polymers bearing the polar functionalities would be more optically homogeneous and have high glass-transition temperatures because the bulky and unsymmetrical polycyclic structure in the main chain should prevent crystallization.As already having been pointed out,however,these ring-opening metathesis polymers have poor thermal stability due to the unsaturation.