1.1: triphenylphosphine; di-isopropyl azodicarboxylate / toluene / 12 h / 0 - 40 °C / |Inert atmosphere 2.1: diisobutylaluminium hydride / hexane / 2.17 h / -78 °C / |Inert atmosphere 3.1: manganese(IV) oxide / dichloromethane / 0.5 h / 20 °C / |Inert atmosphere 4.1: n-butyllithium / hexane; tetrahydrofuran / 0.5 h / -30 - -10 °C / |Inert atmosphere 4.2: 1 h / -30 - 20 °C / |Inert atmosphere View Scheme

1: 58 percent / POCl3 / pyridine / 22 h / 95 °C 2: 0.53 g / LiAlH4 / diethyl ether / from -40 to 0 degC over 1 h 3: MnO2 / hexane / 16 h / Ambient temperature View Scheme