Chan−Lam cross-coupling between boronic acids and sulfonyl azides mediated by the combination of heterogeneous catalyst Cu-USY and NaBH4

Abstract

Background

The Chan-Lam cross-coupling reaction represents one of the most versatile and promising methods for C − N bond construction in chemistry. However, designing effective and stable catalysts remains challenging.

Method

Cu-USY was prepared from ultra-stable Y (USY) zeolite as the framework and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS). thermogravimetric analysis (TGA) etc. The catalytic performance was investigated through the reaction of phenylboronic acids and sulfonyl azides in the absence of ligand, with products characterized by NMR. Mechanistic studies was conducted accordingly.

Significant findings

It has been proved that Cu was well immobilized on the surface and internal cages of USY to enhance the selectively, and in this case, the homocoupling of boronic acids was greatly suppressed. The experimental observations and mechanistic studies indicated that NaBH₄ played dual roles as both base to promote the N₂ release/nitrene formation and reductant to regenerate Cu(I) species in situ. Notably, our method exhibits broad functional groups tolerance, demonstrating good potential in organic synthesis and molecular modification. This work provides an alternative strategy for the synthesis of high performance and recyclable heterogeneous Cu catalyst with good potential practicalities during the C − N bond formation.