Crosslinking of gelatin by ring opening metathesis under aqueous conditions—an exploratory study

Ring-opening metathesis catalysis has received little attention as a means to functionalize or crosslink biopolymers in water since the required catalysts are usually not stable under these conditions. However, biopolymer solubility suggests such a procedure. We show that Grubbs first and second generation catalysts (in emulsion) as well as a water-soluble Hoveyda-Grubbs catalyst can be applied to crosslink glycidyl methacrylated gelatin with norbornene dicarboxylic acid in water by a cross metathesis-ring opening metathesis approach. A mechanistic study suggests that cross metathesis between the functionalized polymer and the cyclic olefin acts as an initiating step for the crosslinking reaction. Copyright © 2014 John Wiley & Sons, Ltd.