Synthesis of linear and branched polyketones from the Rh complex catalyzed living alternating copolymerization of (4-alkylphenyl)allene with CO

Controlled and Living Polymerizations Induced with Rhodium Catalysts. A Review

“…These catalysts are active in polymerization of aryl as well as alkyl propadienes and they show high initiator efficiency (practically 100%). The polymers prepared are of low polydispersity and their number-average molecular weight, M n is close to that calculated from the monomer-to-catalyst molar ratio, indicating the living character of the polymerization 28 . These polyketones can also be prepared as polymer networks if a difunctional monomer such as dipropadienylbenzene is added to the polymerization mixture.…”

“…6 Formation of rhodium η 3 -propadiene complex and rhodacyclopentane species copolymerization of substituted propadienes with carbon monoxide to give alternating copolymers of the polyketone class [28][29][30] (Fig. 7).…”

“…They also found that values of polymer molecular weight were not reproducible, which they ascribe to complications associated with increasing viscosity of the neat reaction mixture at the end of polymerization. Later on, Jaska and Manners et al 187 28 Scheme of polymerization of phosphine-borane adducts with Rh catalysts dium compounds also catalyze dehydrocoupling of amino-borane adducts, however, only cyclic oligomers are obtained in this reaction. Recently, also fluorinated polyphosphinoboranes have been prepared 188 and a rapid progress in synthesis of this type of polymers can be expected.…”

One-Pot Synthesis of Hyperbranched and Star Polyketones by Palladium-Catalyzed Terpolymerization of 4-tert-Butylstyrene, Divinylbenzene, and Carbon Monoxide

“…A Pd–diimine complex 1 in combination with the exchanging bipy ligand at an equimolar amount is employed herein as the catalyst system for the coordinative polymerization. For polyketone synthesis by catalytic alkene-CO alternating copolymerization, Pd-based catalysts with bidentate phosphines or bidentate nitrogen ligands are most commonly used. − While the bidentate phosphine-ligated catalysts are more efficient for copolymerization of ethylene or aliphatic α-olefin with carbon monoxide, − the bidentate nitrogen-ligated catalysts are favored for the copolymerization of vinylarene (such as styrene and TBS) with CO. − To date, various bidentate nitrogen ligands have been successfully applied to Pd-catalyzed TBS/CO copolymerization, including 1,10-phenanthroline, bipy, oxazoline, α-diimine, and pyrazole-based bidentate ligands. − …”

“…However, the synthesis of polyketones with complex topologies such as hyperbranched polyketones or star polyketones (SPKs) has been extremely rare, while they are expected to be valuable with desired properties anticipated. To date, Osakada et al reported briefly in 2000 the only example of branched polyketones (BPKs) by rhodium-catalyzed alternating polymerization of arylallenes and carbon monoxide in the presence of a small amount of difunctional diallenylbenzene as the branching agent . The allene monomer is not a common monomer and requires special synthesis.…”