Transformations of polyketones

Aijunan Palanisamy. (1996). Process of Transformation of Polyketones into the Complex Polyesters US Patent 55506312. International Patent Catalogue C 08 F 20/00. 

Scheme 16 Chemical transformation of polyketones to other functional polymers.

Very interesting transformations of the polyketones into other polymeric materials have been reported. An optically active isotactic poly[l-oxo-2-mefhylpro-pane-l,3-diyl] was reacted with methylenation reagents to give poly[l-methylene-2-methylpropane-l,3-diyl] ]143] apparently without racemization. A similar material was reduced to the corresponding poly[l-hydroxo-2-methylpropane-l,3-diyl] with 40% 1-diastereoselectivity using tetrabutylammonium borohydride [144]. Furthermore, ethene copolymers or efhene-propene terpolymers were transformed into... 

Kohnke et al. also reported the conversion of caUxfurans to hetero-cydophanes containing isopyrazole imits via cydic polyketone derivatives such as 74 [49]. Treatment of polyketone 74 with hydrazine hydrate gave the isopyrazole-based macrocycles 83. The corresponding hex-amer was also prepared by the same protocol. The transformation of... 

Hydroboration of a,C0-dienes with monoalkylboranes gives reactive organoboron polymers which can be transformed into polymeric alcohols or polyketones by carbonylation, cyanidation, or the DOME reaction followed by oxidation (446—448). 

Depending on the reaction conditions, the copolymer product can be isolated in the form of either polyketone as poly(l-oxo-2-raethyltrimethylene) (Chart 7.5a) or polyspiroketal as poly[spiro-2,5-(3-methyltetrahydrofuran)j (Chart 7.5b). This latter can be transformed into the thermodynamically more stable polyketone form, either thermally or by dissolution in HFIP [1, 41, 42]. 

Palladium-catalyzed a-arylation of ketones is performed with arylene dihalides and bifunctional aromatic ketones 148 to result in the bond formation at the r/) -a-carbon of the ketone, leading to polyketone 149. The reaction is carried out in the presence of Pd(0) and various phosphines. Several bidentate phosphines and bulky alkylphosphines such as dppf, BINAP, PCys, and P Bu3 are shown to be effective, while PPh3 results in no reaction. Arylene dibromide and diiodide are applicable as the co-monomers. The polymerization reaction is carried out in THE in the presence of NaO Bu at 75 °C under N2, and polymers 149 are isolated in 60-80% yields (M = 7000-15 000). Polyketone 149 is further transformed to conjugated polymer PPV by reduction of the ketone moiety with LiAlH4 followed by dehydration with an acid (Equation (69)). 

So, when conducting the reaction at 65-85 °C in water, alcohol, ester, acetonitrile, the polyketone particles of size 0.01-100 micrometers transform the polyesters by the oxidation under the peroxide agents per-oxybenzoic, m-chloroperoxybenzoic, peroxyacetic, trifloumperoxyacetic, monoperox rphthalic, monoperox5rmaleine acids, combinations of H2O2 and urea or arsenic acid [405, 406],... 

The relative thermodynamic stability of the two structures is unknown however, it seems to be subject to enthropic factors. The spiroketal structure is particularly stable for norbomenef " or bicyclopentadiene.f" For propene, even if the copolymer is formed with the polyspiroketal structure it transforms easily into the polyketone one when heated or when acidic conditions are applied. The reverse is true for allylbenzene.f For... 

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