SYNTHESIS AND SOLID-STATE C-13 NMR-STUDY OF POLYMER-BOUND TRIPHENYLMETHYL CATIONS

A polymer-bound cation system of the triphenylmethyl type has been syn thesized via a method in which the first step is lithiation of polysty rene. The final step in the synthesis of the polystyrene-bound triphen ylmethyl carbocation system was either conversion of the corresponding polymer-bound triphenylmethyl chloride with AlCI3 or the conversion o f the polymer-bound triphenylmethyl alcohol with perchloric acid. The various functionalized polymer samples were characterized by solid-sta te C-13 NMR, which showed that, for the polymer-bound triphenylmethyl alcohol system, there are 0.59 mmol of carbinol moieties per gram of p olymer. The polymer-bound carbocation system was found to be surprisin gly stable, et en to moisture in air, and can readily be regenerated f rom its hydrolysis product. The polymer-bound carbocation system is ef fective as a catalyst in a Michael addition reaction and as a hydride acceptor reagent in a Dauben-type hydride transfer reaction.