Heterogeneous gold-catalyzed Sandmeyer coupling of aryldiazonium salts with sodium bromide or thiols for constructing C–Br and C–S bonds

Abstract

An efficient heterogeneous gold-catalyzed Sandmeyer coupling of aryldiazonium salts with sodium bromide or thiols for the formation of C–Br and C–S bonds has been achieved in high yields and selectivities under mild conditions by using a bis(diphenylphosphinomethyl)amino-modified mesoporous MCM-41-immobilized gold(I) chloride complex [MCM-41-2Ph₂PAuCl] as the catalyst without using sacrificial oxidants. Vital to the success of this C-heteroatom coupling is the nucleophile-promoted activation of aryldiazonium salts, which can serve as an efficient oxidant for the conversion of Au(I) to Au(III) without the use of a photocatalyst or an assisting ligand. This new heterogenized gold(I) complex can be easily prepared by a simple procedure and recovered via centrifugation, and recycled more than seven times without any significant loss of its catalytic efficiency.