Thiol-Michael coupling and ring-opening metathesis polymerization: Facile access to functional exo-7-oxanorbornene dendron macromonomers

Abstract

Thiol-Michael Coupling and ROMP: Facile Access to Functional exo-7-Oxanorbornene Dendron Macromonomers Nucleophile-mediated thiol-Michael coupling is employed to prepare a small library of functional thioether-based dendron monomers from novel di- and tetra-acrylate functional ring-opening metathesis polymerization (ROMP)-active exo-7-oxanorbornene-based monomers. The ROMP (co)polymerization of these novel monomers is evaluated with Grubbs 1st and 3rd generation initators. This paper describes the synthesis of the 2- and 4-functional acrylic exo-7-oxanorbornene species 2-((2-((3aR,7aS)-1,3-dioxo-1,3,3a,4,7,7a-hexahydro-2H-4,7-epoxyisoindol-2-yl)ethoxy) carbonyl)-2-methylpropane-1,3-diyl diacrylate and (((2-((2-((3aR,7aS)-1,3-dioxo-1,3,3a,4,7,7a-hexahydro-2H-4,7-epoxyisoindol-2-yl)ethoxy) carbonyl)-2-methylpropane-1,3-diyl)bis(oxy))bis(carbonyl))bis(2-methylpropane-2,1,3-triyl) tetraacrylate, and their use as common precursors for the preparation of a small library of dendronized thioether adducts via nucleophile-mediated thiol-Michael coupling chemistry. We subsequently demonstrate that the dendronized monomers can be (co)polymerized via ring-opening metathesis polymerization employing Grubbs'-type Ru-based initiators to give novel functional dendronized (co)polymers of predictable molecular weights and acceptable dispersities (D{stroke}M = M w/ M n). © 2013 Society of Chemical Industry.