Copper Pincer Complexes As Advantageous Catalysts For The Heteroannulation Of Ortho-Halophenols And Alkynes

A new, non-symmetrical copper(II) pincer complex catalyzes much more efficiently the formation of benzofuran by the reaction between ortho-iodophenols and alkynes. The lowest catalyst loadings are realized for this reaction, and bromo-and chlorophenols are heteroannulated for the first time. Strong evidence for hydrophenoxylation and intra-molecular halogen atom-transfer steps catalyzed by this remarkably active, recyclable homogeneous catalyst is provided.