Nucleophilic aliphatic polymers from

A large cationic radius generally increases the nucleophilic reactivity of the anion in an ion pair. A small cationic radius results in stronger electrostatic attraction and lesser reactivity of the anion. Catalysts with the active site separated from the polymer backbone by an aliphatic chain have higher activity than those prepared by quatemi-zation of a chloromethylpolystyrene with a tertiary amine or tertiary phosphine, leaving only one carbon atom between the active site and the aromatic ring. 

Polymer-bound chiral hydrazines have been synthesized to furnish a-branched amides (Scheme 12.17) [13, 23], Enantiopure (i-methoxyamines 37 and 38, derived from readily available hydroxyproline and N,N-dibenzylleucinol, respectively, have been attached to solid support and transformed into the corresponding hydrazine auxiliaries 39 and 40 via several steps. The synthesis of a series of enantiomerically enriched a-branched amides required the coupling of aliphatic and aromatic aldehydes to form hydrazones 41 and 42 followed by the addition of different nucleophiles. Cleavage of the N-N bond of the resulting hydrazines 43 and 44 led to a-branched amines 45. Further conversion with benzoyl chloride or acetyl chloride furnished amides 46 in yields of 24—51% and 50-83% ee. 

PAES with pendant sulfonated aliphatic side chains have been prepared by a nucleophilic substitution polycondensation and sulfoakylation reaction [94]. 3, 3-Bis(4-hydroxyphenyl)-l-isobenzopyrrolidone and 4,4 -difluorodiphenyl sulfone or 3,3, 4,4 -tefrafluoro-diphenylsulfone were used as monomers. Membranes formed from these polymers displayed a low water uptake and swelling ratio both at ambient temperature... 

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