Ring-opening metathesis polymerization-derived, polymer-bound Cu-catalysts for click-chemistry and hydrosilylation reactions under micellar conditions

Abstract

Ring-opening metathesis polymerization has been used for the synthesis of the amphiphilic block-copolymer poly(M1-co-M3)-b-poly(M2) from the hydrophilic monomer 5-{2-[2-(2-methoxy-ethoxy)-ethoxy]-ethoxymethyl}-7-oxabicyclo[2.2.1]hept-2-ene (M2), and the hydrophobic monomers endo,exo-5-decyloxymethyl-bicyclo[2.2.1]hept-2-ene (M1) and 1,3-di(1-mesityl)-4-{[(bicyclo[2.2.1]hept-5-en-2-ylcarbonyl)oxy]methyl}-4,5-dihydro-1H-imidazol-3-ium carboxylate (M3). Poly(M1-co-M3)-b-poly(M2) was loaded with Cu and the resulting Cu(I)-loaded polymer poly(M1-co-M3)-b-poly(M2)-Cu was used for a series of Cu-catalyzed reactions under micellar conditions, i.e. for the [3 + 2] cycloaddition of azides to alkynes and for carbonyl hydrosilylation reactions. Under such micellar conditions, the polymer-bound Cu-catalyst was found to be an efficient catalyst for all reactions investigated. Turn-over numbers (TONs) in cycloaddition reactions were in the range of 200-375, those in hydrosilylation reactions approximately 2000 allowing for Cu-loadings of 0.05 mol% with respect to substrate.