LITHIATION OF CROSSLINKED POLYMERS PREPARED USING 2-VINYLTHIOPHEN - APPLICATION TO THE PREPARATION OF POLYMER-SUPPORTED REAGENTS

Copolymers of 2-vinylthiophen and divinylbenzene and of 2-vinylthiophen, styrene, and divinylbenzene were prepared by benzoyl peroxide-initiated suspension polymerizations. The polymers were lithiated using n-butyllithium, and the lithiated materials reacted further to give polymers containing carboxylic acid, triarylphosphine or aldehyde functional groups. The lithiation reactions were complex and the percentage of the thienyl residues that reacted depended critically on the proportions of 2-vinylthiophen and styrene used in the preparation of the polymers and on the solvent used in the lithiation reaction. The results strongly suggest that the extent of lithiation was limited by the diffusion of the metallating agent into the crosslinked polymer. The polymers containing triarylphosphine substituents, used in conjunction with bromine or with tetrabromomethane, were effective reagents for the conversion of alcohols into alkyl bromides. © 1990.