Synthesis of carbene precursors containing substituted benzyl group

In this study, diamines which were prepared from aromatic aldehydes and 1,2-diamines reduced with sodium borohyride to secondary diamines in methanol at room temparature. Perhydrobenzimidazolium (3a-e) and imidazolinium (3f-l) salts were synthesized by the reaction of secondary diamines with triethyl ortoformate in the presence of ammonium chloride. The structure of all compounds synthesized were determined by using spectroscopic techniques such as 1H-NMR, 13C-NMR, IR and elemental analyses. These salts were used as catalyst in Heck coupling reactions between styrene with aryl bromides and stilbene derivatives were obtained in high yields.