1: ethyl (2Z)-3-iodo-3-phenylprop-2-enoate With iso-propylmagnesium bromide in tetrahydrofuran T=-20°C; 0.5 h; 2: p-toluenesulphonyl cyanide in tetrahydrofuran T=-40 - -20°C; Further stages.;

Rh2(Piv)4 in dichloromethane T=-78 - 20°C; 1 h; Inert atmosphere; optical yield given as percent de;