lithium azide; benzoic acid in N,N-dimethyl-formamide T=130°C; 4 h;

1: 80 percent / triphenylphosphine, HN3, diethyl azodicarboxylate / dimethylformamide; toluene / 2 h / 40 °C 2: 63 percent / triphenylphosphine, diethyl azodicarboxylate / toluene; dioxane / 4 h / 60 °C 3: 72 percent / triphenylphosphine / dimethylformamide; toluene / 4 h / 60 °C 4: 48 percent / LiN3, benzoic acid, / dimethylformamide / 4 h / 130 °C View Scheme

1: 63 percent / triphenylphosphine, diethyl azodicarboxylate / toluene; dioxane / 4 h / 60 °C 2: 72 percent / triphenylphosphine / dimethylformamide; toluene / 4 h / 60 °C 3: 48 percent / LiN3, benzoic acid, / dimethylformamide / 4 h / 130 °C View Scheme

1: 80 percent / diethyl azodicarbonate, triphenylphosphine / dimethylformamide; toluene / 4 h / Heating 2: 48 percent / LiN3, benzoic acid, / dimethylformamide / 4 h / 130 °C View Scheme

1: 72 percent / triphenylphosphine / dimethylformamide; toluene / 4 h / 60 °C 2: 48 percent / LiN3, benzoic acid, / dimethylformamide / 4 h / 130 °C View Scheme

p-toluenesulfonyl chloride in pyridine T=20°C; 16 h;