Ring Opening Metathesis Polymerization (ROMP) of cis ‐ and trans ‐3,4‐Bis(acetyloxymethyl)cyclobut‐1‐enes and Synthesis of Block Copolymers

Summary: The synthesis and living ring opening metathesis polymerization (ROMP) of diacetate functionalized cyclobutene derivatives cis ‐3,4‐bis(acetyloxymethyl)cyclobutene ( 2 ) and trans ‐3,4‐bis(acetyloxymethyl)cyclobutene ( 3 ) were investigated with the functional group tolerant initiators (PCy 3 ) 2 (Cl) 2 RuCHPh ( I ) and (SIMes)(PCy 3 )(Cl) 2 RuCHPh ( II ) (SIMes: 1,3‐dimesityl‐4,5‐dihydroimidazol‐2‐ylidene). The kinetic parameters of the ROMP initiated by the ruthenium alkylidene complexes I and II were determined and correlated to monomer stereochemistry. The cis isomer 2 was found to be more reactive than the trans isomer 3 and to generate functional polymers of narrow molecular weight distribution especially with the classical “first generation Grubbs catalyst” I . Block copolymers containing 2 and cyclooctadiene ( COD ) or norbornene ( NBE ) were synthesized. Block copolymer poly(2‐ b ‐COD) was hydrolyzed and converted to a material with a block bearing hydrophilic alcohol functional groups and hydrophobic block.SEC elution profiles: poly(2) prepolymer and block copolymer poly(2‐ b ‐COD) .