ABSTRACT
The superior catalytic abilities of 4-dialkylaminopyridines as acylation catalysts were first demonstrated over 20 years ago. Since that time 4-dimethylaminopyridine has emerged as the preferred catalyst for a variety of synthetic transformations under mild conditions, particularly acylations, alkylations, silylations, esterifications, polymerizations, and rearrangements. Its use has been particularly beneficial in the acylation of sterically hindered alcohols where only low conversions are possible under normal conditions. The immobilization of 4-dimethylaminopyridine (DMAP) as a polymer-supported catalyst offers a number of chemical, processing and environmental advantages. As such, a polymer-supported DMAP can simplify separation and purification procedures, be used in excess—important in equilibrium reactions, increase efficiency by recycling, decrease environmental impact, and reduce toxicity.
