Synthesis of (R,R)- and (S,S)-Norphos

Oxidation of ( E)-1,2-bis(diphenylphosphanyl)ethene with hydrogen peroxide gave ( E)-1,2-bis(diphenylphosphoryl)ethene. Diels-Alder reaction of ( E)-1,2-bis(diphenylphosphoryl)ethene with cyclopentadiene yielded 2,3-bis(diphenyl--phosphoryl)bicyclo[2.2.1]hept-5-ene (NorphosO). RAC-NorphosO was resolved with O, O-dibenzoyltartaric acid. ( R, R)- and ( S, S)-NorphosO were reduced with trichlorosilane to give 2,3-bis(diphen-ylphosphanyl)bicyclo[2.2.1]hept-5-ene [( R, R)- and ( S, S)-Norphos].