CuI/I2-promoted electrophilic tandem cyclization of 2-ethynylbenzaldehydes with ortho-benzenediamines: synthesis of iodoisoquinoline-fused benzimidazoles.

An efficient tandem route to the synthesis of iodoisoquinoline-fused benzimidazole derivatives including an iodocyclization strategy has been developed. In the presence of CuI, a variety of 2-ethynylbenzaldehydes underwent the tandem reaction with benzenediamines and iodine to afford the corresponding iodoisoquinoline-fused benzimidazoles in moderate to good yields.