Vinylic Addition Polynorbornene in Catalysis

Abstract

Vinylic addition polynorbornenes (VA-PNB) result from the insertion polymerization of norbornene or specific norbornene derivatives catalyzed by transition metal complexes. The VA-PNB skeleton is completely aliphatic and keeps the bicyclic structure of norbornene. This saturated polymer is thermally and chemically very stable and it is a very robust scaffold to support catalysts or reagents for catalytic applications. Several VA-PNBs are now available with suitable functional groups (halogen, alkenyl, carbonates) that can be used as starting materials to introduce the functional-ization of choice by post-polymerization reactions. This has been applied to anchor organocatalysts on VA-PNB as well as ligands that can be used to synthesize supported metal catalysts. The reported examples of the use of VA-PNB-linked catalysts and their recyclability will be presented. VA-PNBs have also proved useful in the context of organotin chemistry to solve the problem of tin contamination by an efficient separation and the reuse of tin byproducts. Its uses in the Stille cross-coupling reaction and tin-hydride radical processes will be discussed. 2 3 4 5 6 7 8

Poly(vinylbenzyl chloride-co-divinyl benzene) polyHIPE monolith-supported o-hydroxynaphthaldehyde propylenediamine Schiff base ligand complex of copper(ii) ions as a catalyst for the epoxidation of cyclohexene

“…3,[12][13][14] Some efforts were made to increase the loading capacity of supports by controlling their swelling properties and improving the stability of supported catalysts. 4,15 Property modication in polymer gel-bead supports was found to be more useful in continuous ow reactors than batch reactors. 14,[16][17][18][19] However, polymer gel-beads suffered from a channeling effect, which made interior active sites to remain unutilized in ow-through processes.…”

Highly efficient vinylic addition polymerization of 5-vinyl-2-norbornene using benzylic palladium complexes as precatalysts

“…The activities found are the highest described so far for this alkenylnorbornene derivative. The catalytic species are generated from a palladium η (3,4) leads to insertion of VNB into the Pd-C(benzyl) bond and the incorporation of the benzyl moiety in the polymer. This is a good example that shows how the cationic palladium species favor the 1,2-olefin insertion vs. a β-H elimination.…”

“…2 As a result, the introduction of functional groups anchored to the main-polymer skeleton relies on the post-polymerization functionalization of a few types of suitable precursor VA-PNBs, such as ω-bromoalkyl substituted VA-PNBs. 3,4 Therefore, the discovery of new catalysts for the efficient VA-polymerization of norbornene derivatives is still a challenge. Alkenyl norbornenes are attractive monomers for the VApolymerization of the norbornene moiety (Scheme 1).…”

Synthesis of End-Functionalized Poly(norbornenes) and Poly(ethylidene norbornenes) Using a Pd(II) Catalyst in Combination with Chain Transfer Agents

“…Numerous transition-metal catalysts are effective for the polymerization of norbornene-type monomers, and normally very high molecular weight polymers result due to the reluctance of metal σ-norbornyl intermediates to undergo β-hydride elimination . Goodall and co-workers pioneered the use of α-olefins as chain transfer agents to control the molecular weights of poly­(norbornenes), PNBs .…”