Synthesis of 2,2’-Bipyridine Via a Phosphorus Extrusion Reaction

Abstract

The formation of carbon-carbon bonds has long been a synthetic goal for chemists. This has lead to the development of many novel and highly synthetically useful reactions. One of the most notable reactions to form sp2 C - sp2 C bonds has been the cross-coupling reaction.1 Although these transformations have been very well studied and have recently produced a Nobel Prize, these transformations suffer from two drawbacks.1 First, they often require expensive and exotic transition metal complexes and second, the reaction conditions often require inert or anhydrous conditions.1 Therefore, any reactions which can substitute these reactions that do not require expensive metals or can be run under less sensitive conditions are in great demand. Our research group in conjunction with the Wicker group at Southeastern Louisiana University has developed a phosphonium species that we are exploring as a novel precursor for the formation of 2,2’-bipyridine and its derivatives. 2,2’-bipyridines and their derivatives are of increasing interest to the chemistry community due to their unique properties as ligands.2 However, the majority of syntheses of these species rely on the use of cross coupling reactions to form unsymmetrically substituted bipyridine species. Our protocol, once optimized, will allow us to form these species without the use of cross-coupling reactions.