Copper(I)-Catalyzed Formation of Isoquinoline and Quinoline Substituted Isobenzofurans

An efficient synthetic organic transformation was developed to access isoquinoline-substituted isobenzofurans by reaction of substituted 1,5-diynes with isoquinoline N-oxides. Moderate to excellent yields of isoquinoline-derived isobenzofurans were achieved by formation of a new C–C and two C–O bonds in the presence of copper catalyst in one pot. whereas quinoline-substituted isobenzofurans were obtained when the reaction was conducted using quinoline N-oxides and 1,5-diynes in the presence copper catalyst.