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

1.1: LDA; TMS-Cl / tetrahydrofuran / 1 h 1.2: DBU / toluene / 18 h / 20 °C 1.3: 27 percent / HCl / methanol; H2O / 4 h 2.1: 92 percent / PPh3; DIAD / tetrahydrofuran / 5 h View Scheme