Organozinc Derivatives of Diazines, Metalation of Diazines XXIII

Some organozinc derivatives of diazines have been prepared from lithiated diazines and zinc chloride.They reacted in cross coupling reactions with iodobenzene, 2-bromopyridine and 5-bromopyrimidine.The use of sonication, for the first time in a Negishi reaction, lowered the reaction times significantly and improved the yields.Since ten years we have investigated the synthesis of organometallics of diazines via lithio derivati-1-8 ves.These metalations were very often successful but, except in few cases, the lithio derivatives were reacted at -75°C because they are not stable at higher temperatures.