1: With chloro-trimethyl-silane; lithium diisopropyl amide in tetrahydrofuran 1 h; 2: With 1,8-diazabicyclo[5.4.0]undec-7-ene in toluene T=20°C; 18 h; 3: With hydrogenchloride in methanol; water 4 h; Further stages.;

di-isopropyl azodicarboxylate; triphenylphosphine in tetrahydrofuran Mitsunobu reaction; 5 h;