Enantioselective synthesis of a conformationally rigid, sterically encumbered, 2-arsino-7-phosphanorbornene

Convenient access to the enantiomerically pure, conformationally rigid, ligand [5-(dicyclohexylarsino)-2,3-dimethyl-7-phenyl-7-phosphabicyclo[2.2.1]hept-2-ene has been established by intramolecular [4+2]-Diels–Alder cycloaddition between dicyclohexylvinylarsine and 3,4-dimethyl-1-phenylphosphole using chiral organopalladium(II) complexes containing orthometallated (S)-1-α-(dimethylamino)ethylnaphthalene or (R)-2-α-(dimethylamino)ethylnaphthalene as the reaction templates. The ligand was displaced from the palladium complex with cyanide and reacted with [(η6-arene)RuCl2]2 and NH4PF6 to form diastereomeric [(η6-arene)Ru(PAs)Cl]PF6 complexes, chiral at ruthenium. New complexes have been characterized by elemental analyses, electrochemistry, and electronic, circular dichroism, 1H-, 1H{31P}-, 13C{1H}- and 31P{1H}-NMR spectroscopies, and in several cases, by X-ray crystallography.