Practical in situ-generation of phosphinite ligands for palladium-catalyzed carbonylation of (hetero)aryl bromides forming esters

Abstract

An effective method for alkoxycarbonylation of (hetero)aryl bromides is developed in the presence of in situ-generated phosphinite ligands ^tBu₂POR (R = ⁿBu, ⁿPr, Et or Me). For this purpose commercially available ^tBu₂PCl was used as the pre-ligand in the presence of different alcohols. For the first time cross coupling reactions with two alcohols – one generating the ligand, the other used as substrate – were developed. Through this method, ligand optimization can be performed in a more efficient manner and the desired products could be obtained with good yields and selectivity.