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 aryl-boronic 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-beta-cyclodextrin, which is readily available and structurally simple, but has not previously been explored as a catalyst.