CuII–β‐Cyclodextrin Complex as a Nanocatalyst for the Homo‐ and Cross‐Coupling of Arylboronic Acids under Ligand‐ and Base‐Free Conditions in Air: Chemoselective Cross‐Coupling of Arylboronic Acids in Water

We report here the transition‐metal‐catalyzed chemoselective cross‐coupling of arylbroronic acids in high yields without using ligand or base. We have developed an efficient copper‐catalyzed protocol for the homocoupling and cross‐coupling of arylboronic acids. The protocol is also suitable for the cross‐coupling of aliphatic primary amines with arylboronic acids. Aminophenols and primary amines bearing an alcoholic substituent on the aliphatic chain were coupled with arylboronic acids, and the products were obtained with high C–N coupling selectivity. An effective catalyst was Cu 2 –β‐cyclodextrin, which is readily available and structurally simple, but has not previously been explored as a catalyst.