Facile synthesis of alkyl- and arylboronate esters enabled by a carbon nanotube supported copper catalyst

An efficient synthesis of alkylboronate esters via alkyl halide borylation catalysed by copper nanoparticles stabilised on nitrogen-doped carbon nanotubes (N-CNT) is reported. This nanocatalyst provides practical access to alkylboronate esters at room temperature in 1 h, with good functional group tolerance. The procedure is also applicable to the borylation of benzyl chlorides and bromides. Radical clock experiments suggest that the reaction involves a radical pathway. The catalyst can be recycled up to ten runs without appreciable loss in the activity. In addition, we demonstrated the use of this supported copper catalyst for the anti-Markovnikov-selective hydroboration of vinylarenes and borylation of aryl halides with B(2)pin(2), providing alkyl- and arylboronate esters, respectively, in good to excellent yields.

Automated summary

This paper reports an efficient synthesis of alkylboronate esters via the catalysis of copper nanoparticles stabilised on nitrogen-doped carbon nanotubes. The nanocatalyst allows practical access to alkylboronate esters at room temperature in a short time period and exhibits good functional group tolerance. Radical clock experiments suggest that the reaction proceeds through a radical pathway. Additionally, the catalyst can be recycled multiple times without significant loss in activity. Furthermore, the supported copper catalyst is demonstrated to be applicable for the anti-Markovnikov-selective hydroboration of vinylarenes and borylation of aryl halides, providing alkyl- and arylboronate esters with high yields.