1.1: hypophosphorous ether; sodium azide; sulfuric acid; acetic acid / water / 39.5 h / 5 °C 1.2: pH 8 2.1: triphenylphosphine; di-isopropyl azodicarboxylate / tetrahydrofuran / 0.33 h / 0 °C / Inert atmosphere 2.2: 16 h / 20 °C / Inert atmosphere 3.1: water; lithium hydroxide hydrate / tetrahydrofuran; methanol / 2 h / 0 °C View Scheme

isopentyl nitrite in N,N-dimethyl-formamide T=65°C; 0.5 h;

Multi-step reaction with 2 steps 1.1: hypophosphorous ether; sodium azide; sulfuric acid; acetic acid / water / 39.5 h / 5 °C1.2: pH 82.1: triphenylphosphine; di-isopropyl azodicarboxylate / tetrahydrofuran / 0.33 h / 0 °C / Inert atmosphere2.2: 16 h / 20 °C / Inert atmosphere