A new strategy for the one pot synthesis of (aryloxyimino)ethylcoumarins promoted by CuCl2

Cupric chloride showed efficient catalytic activity for the cross coupling reaction of arylboronic acids and (hydroxyimino)ethylcoumarins at room temperature in the presence of NEt3 as base. A simple and convenient protocol for the synthesis of O-aryloxime ethers having the highly base sensitive coumarin nucleus is reported. O-Aryloxime ethers are important as they provide access to scaffolds for the generation of various biologically active compounds. They are potential precursors to benzofurans and benzisoxazoles.