Kryptofix 5 as an inexpensive and efficient ligand for the palladium-catalyzed Mizoroki-Heck reaction

A novel complex of PdCl2 with a multidentate cryptand ligand, Kryptofix 5, has been prepared and characterized by various techniques including H-1- and C-13 NMR spectroscopy, Fourier transform infrared (FT-IR), Raman, ultraviolet and visible (UV-VIS) spectroscopy, inductively coupled plasma (ICP), CHN elemental and energy dispersive X-ray analysis (EDX). This heat- and air-stable complex was utilized as a highly active catalyst for the Mizoroki-Heck reaction of aryl halides with various olefins. Interestingly, it was found that aryl bromides as well as aryl iodides were efficiently cross-coupled with terminal alkenes at 130 degrees C in 10min. Furthermore, the least reactive aryl chlorides reacted with styrene to obtain the desired products in acceptable yields.