Access to Multiblock Copolymers via Supramolecular Host-Guest Chemistry and Photochemical Ligation

We combine supramolecular host-guest interactions of beta-cyclodextrin (CD) with light-induced DieIs-Alder reactions of 2-methoxy-6-methylbenzaldehyde (photoenol, PE) for the formation of multiblock copolymers. Via the synthesis of a new bifunctional chain transfer agent (CTA) and subsequent reversible addition-fragmentation chain transfer (RAFT) polymerization, we introduce a supramolecular recognition unit (tertbutyl phenyl) and a photoactive unit (photoenol) to a polymer chain in order to obtain an alpha,omega-functionalized polymeric center block, having orthogonal recognition units at each chain end. Multiblock copolymers are formed via the light-induced reaction of the photoenol with a maleimide-functionalized polymer chain and the supramolecular self-assembly of the tert-butyl phenyl group with the beta-CD end group of a third polymer chain. By employing the fast and efficient photoinduced Diels-Alder reaction in combination with supramolecular host-guest interactions, a novel method for macromolecular modular ligation is introduced.