Ru-Catalyzed Isomerization Provides Access to Alternating Copolymers via Ring-Opening Metathesis Polymerization

Abstract

We describe an isomerization–alternating ROMP protocol that gives linear copolymers with rigorous sequence alternation. Bicyclo[4.2.0]­oct-7-ene-7-carboxamides of primary amines are isomerized in the presence of (3-BrPyr)₂Cl₂(H₂IMes)­RuCHPh to the corresponding bicyclo[4.2.0]­oct-1(8)-ene-8-carboxamides in which the olefinic bond is tetrasubstituted. The <i>isomerized</i> amides undergo alternating ring-opening metathesis polymerization with cyclohexene to provide soluble and linear copolymers with molecular weights up to ∼130 kDa. This process provides efficient entry to strictly alternating copolymers that can display diverse functional groups