1: (E)-1-bromo-1-trimethylsilyl-2-phenylethene With tert.-butyl lithium in diethyl ether; pentane T=-78°C; 2: 2-benzyl-3-phenylpropionaldehyde in diethyl ether; pentane T=-78 - 0°C; 3: in diethyl ether; N,N-dimethyl-formamide; pentane T=50°C; Peterson allenation; Further stages.;