Palladium-catalysed carbonylation of aryl halides in ionic liquid media: high catalyst stability and significant rate-enhancement in alkoxycarbonylation

Abstract

Palladium-catalysed carbonylation of aryl halides with alcohols or NEt₂H proceeds in ionic liquid media (1-butyl-3-methylimidazolium tetrafluoroborate or hexafluorophosphate). The catalyst/ionic liquid mixture could be recycled, after separation of the product by either distillation or extraction with ether. Carbonylation with alcohols forming benzoates was greatly accelerated by the use of ionic liquid.