Pd(OAc)2/DABCO as an efficient and phosphine-free catalytic system for the synthesis of single and double Weinreb amides by the aminocarbonylation of aryl iodides

Abstract

This work reports a mild, stable and efficient Pd(OAc)₂/DABCO catalysed protocol for the synthesis of single and double Weinreb amides. Double Weinreb amides, having 1,4-phenylene- and biphenylene-linkers – important backbones for the synthesis of biologically active symmetrical resorcylate oligomer units – were synthesized by the double carbonylation of aryl diiodides. Notably, the reaction does not require any expensive or air/moisture sensitive phosphine ligands. DABCO was found to be an inexpensive and stable ligand for the Pd(OAc)₂ catalysed carbonylation of aryl iodides under an atmospheric pressure of carbon monoxide, and offered excellent yields of the single and double Weinreb amides.