1.1: triethylamine / dichloromethane / 0.17 h / 0 °C / Inert atmosphere 2.1: sodium azide / N,N-dimethyl-formamide / 20 - 50 °C / Inert atmosphere 3.1: water; triphenylphosphine / tetrahydrofuran / 10 h / 40 °C / Inert atmosphere 3.2: Inert atmosphere 4.1: tetrabutyl ammonium fluoride / tetrahydrofuran / 0 °C / Inert atmosphere View Scheme

1: 1.) PPh3, DEAD / 1.) THF, 10 min, 2.) THF, RT, overnight 2: Bu4NF / tetrahydrofuran View Scheme

carbon tetrabromide; triphenylphosphine in tetrahydrofuran 6 h; Ambient temperature;

1: o-iodoxybenzoic acid / dimethylsulfoxide / 2 h 2: 4.28 g / 2-methyl-2-butene; aq. sodium chlorite; sodium dihydrogen phosphate / 2-methyl-propan-2-ol / 1 h / 0 °C View Scheme

With  tetra-n-butylammonium tribromide in  methanol 0.35 h;