A novel method of complete activation by carbonyldiimidazole: application to ester synthesis

The activation of carboxylic groups by carbonyldiimidazole (CDI) results in the presence of excess CDI; it is shown that this reacts rapidly with the target hydroxyl groups under acylation conditions, thus preventing the desired acylation even when an excess of reagent is present and resulting in poor yields. The methods described result in rapid, complete, and convenient removal of the excess CDI. This procedure thus permits the use of …