Suzuki Coupling Polymerization

From Ranger, M., Rondeau, D., and Leclerc, M., Macromolecules, 30 7686, 1997. Copyright 1997, American Chemical Society, Washington, D.C. With permission. 

From Sonar, P., Zhang, J., Grimsdale, A.C., Mullen, K., Surin, M., Lazzaroni, R., Leclere, P., Tierney, S., Heeney, M., and McCulloch, I., Macromolecules, 37 709, 2004. Copyright 2004, American Chemical Society, Washington, D.C. With permission. 

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Suzuki coupling chemistry of benzene boronic acid derivatives and haloben-zenes using a Pd(0) catalyst has also been employed for the synthesis of substituted PPPs as illustrated by the A-B type monomer 16 [67-73]. These initial syntheses were carried out under heterogeneous conditions at a basic pH as illustrated by Scheme 21. Such Suzuki coupling polymerizations are rather attractive alternatives as a wide variety of functional groups can be tolerated with minimal interference in the coupling scheme. 

Zhang XJ, Bian N, Mao LJ et al (2012) Porous polybenzimidazoles via template-free suzuki coupling polymerization preparation, porosity, and heterogeneous catalytic activity in kno-evenagel condensation reactions. MacromolChem Phys 213 1575-1581... 

Recently, Seyler et al. reported a continuous-flow methodology for Suzuki coupling polymerization. poly(9,9-dioctylfluorene) (PFO) using this method shows a quite high molecular weight of 62 000 within only 30 min. This reaction time is comparable to that of microwave-assisted polymerization. 

SCHEME 9 The Suzuki coupling polymerization to a water-soluble PPP. 

Hu et al. [31] reported a new type of macro molecular chiral catalysts for asymmetric catalysis using Suzuki coupling polymerization and obtained optically active ephedrine-bearing dendronized polymers. Their finding showed that the optically active dendronized polymers have characteristics joined features like huge numbers of catalytic sites, more solubility and nanoscopic dimensions towards more acceptable in comparison to its existing chiral catalysts of linear polymeric and dendritic nature. 

Suzuki coupling polymerization Bromo-alkane functionalized polymers Glucothiose Thioetherification reaction — None (linear polymer) [103]... 

At about die same time, die application of the Suzuki coupling, the crosscoupling of boronic acids widi aryl-alkenyl halides in die presence of a base and a catalytic amount of palladium catalyst (Scheme 9.12),16 for step-growth polymerization also appeared. Schliiter et al. reported die synthesis of soluble poly(para-phenylene)s by using the Suzuki coupling condition in 1989 (Scheme 9.13).17 Because aryl-alkenyl boronic acids are readily available and moisture stable, the Suzuki coupling became one of die most commonly used mediods for die synthesis of a variety of polymers.18... 

Pu and co-workers incorporated atropisomeric binaphthols in polymer matrixes constituted of binaphthyl units, the macromolecular chiral ligands obtained being successfully used in numerous enantioselective metal-catalyzed reactions,97-99 such as asymmetric addition of dialkylzinc reagents to aldehydes.99 Recently, they also synthesized a stereoregular polymeric BINAP ligand by a Suzuki coupling of the (R)-BINAP oxide, followed by a reduction with trichlorosilane (Figure 10).100... 

Ruthenium-catalysed Ring-Opening Metathesis Polymerization (ROMP) 29 526 529 (Equation 10) and Pd(tppms)3-catalysed synthesis of water soluble poly-(p-phenylene) derivatives (Equation ll).530 The latter is a special example of a Suzuki coupling (see earlier). 

Water-soluble poly(p-phenylene) 24, shown in Scheme 29, was prepared by the introduction of carboxylic acid pendant substituents along the p-phenylene chains [102]. In initial work in this area, a dicarboxy-substituted dibromobiphe-nyl was polymerized with 4,4f-biphenyl bis-boronic acid via Suzuki coupling... 

The microreactor plant will be equipped with the process control and online analysis [47]. The Suzuki coupling reaction is investigated as a common synthetic route for polymeric semiconductors. The transfer of the developed microflow process into chemical production is accompanied by economic and ecologic evaluations. 

The successful demonstration of the fluorous biphasic concept for performing organometallic catalysis sparked extensive interest in the methodology and it has subsequently been applied to a wide variety of catalytic reactions, including hydrogenation [59], Heck and Suzuki couplings [60, 61] and polymerizations [62]. The publication of a special Symposium in print devoted to the subject [63] attests to the broad interest in this area. 

Although side reactions associated with the supporting phospine ligands do not greatly affect small molecule couplings, they can affect polymerizations dramatically. The effect of one of these side reactions will be discussed. A general catalytic cycle for the Suzuki coupling process is shown in Scheme 1. 

As was shown earlier with the Suzuki coupling reactions, organopalladium intermediates can show good stability to water and other protic sources. This stability has been exploited in the synthesis of polyacetylene under air- and moisture-stable conditions. It was found that simple palladium(II) salts (PdCl2, Pd(CH3C02)2, etc.) can be used to initiate the 1,2-insertion polymerization of strained cyclic alkenes in water (eq. (8)) [31]. Once formed, poly-8 can be converted to polyacetylene through a retro-Diels-Alder reaction. 

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