1: 3,3'-All2-2,2'-O2P-N[(S)-CH(Ph)Et]2-1,1'-Ph2 / copper thiophenecarboxylate / diethyl ether; toluene / 16 h / -35 °C 2: 80 percent / NaNO2; AcOH / dimethylsulfoxide / 24 h / 35 °C View Scheme