Preparation and synthetic application of cellulose-supported phase transfer catalysts

Esterification of potassium cellulosate with chloroacetyl chloride and acryloyl chloride under anhydrous conditions allowed the introduction of chloromethyl and vinyl groups respectively on to the cellulose backbone. Subsequent reactions with tributylphosphine, tributylamine and diethylamine generated a number of immobilized phosphonium and ammonium salts with degrees of functionalization in the range 0.2–0.7 mmol g^?1. These cellulose-supported species were used as phase transfer catalysts in displacement reactions of solid potassium acetate and phenoxide on alkyl halides, and also in the reduction of ketones by sodium borohydride. In favourable cases virtually quantitative conversions were achieved and even non-functionalized cellulose itself displayed some activity. None of the catalysts examined were active in the reduction of acetophenone although the o-hydroxy derivative was readily reduced. At the moment it is not clear whether or not some unfavourable thermodynamic distribution factors are involved; further work is in progress.