Polymerization of enantiomerically pure exo-N-(norborn-2-ene-5-carboxyl)-L-phenylalanine ethyl ester and endo,endo-N,N-(norborn-5-ene-2,3-dicarbimido)-L-valine ethyl ester using novel ruthenium 1,3-diniesityl-3,4,5,6-tetrahydropyrimidin-2-ylidenes

Abstract

The polymerization of two chiral, enantiomerically pure monomers, i.e., exo-N-(norborn-2-ene-5-carboxyl)-L-phenylalanine ethyl ester (1) and endo,endo-N,N-(norborn-5-ene-2,3-dicarbimido)-L-valine ethyl ester (2) using the ruthenium-based, 1,3-dimesityl-3,4,5,6-tetrahydropyrimidin-2-ylidene (Mes2-THP)-derived initiators RuCl2(Mes 2-THP)(=CH-2-(2-PrO-)-5-NO2-C6H3) (3) and RuCl2(Mes2-THP)(=CH-C6H 5)(pyridine) (4), is described. Polymerization of 1 mediated by either 3 or 4 proceeded in a living manner with good control over molecular weight. The polymerization of 2 mediated by either 3 or 4 yielded a polymer with an exclusive all-fraw structure. © 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.