Transition-Metal Complexes with Bidentate Ligands Spanning trans-Positions. I. The synthesis of 2,11-bis(diphenylphosphinomethyl)benzo[c]-phenanthrene,a ligand promoting the formation of square planar complexes

The bidentate ligand 2,11-bis(diphenylphosphinomethyl)benzoc]phenanthrene ( 1 ) was synthesized from 2,11-dimethyl-benzoc]phenanthrene ( 3 ) via the corresponding bromomethyl derivative 9. 3 was obtained from the cyclization with boron trifluoride etherate of 1,1-di-(p-methylphenethyl)-epoxyethane ( 7 ), which was prepared from 1,5-di(p-tolyl)-pentan-3-one ( 6 ).