1: phosphorus tribromide / dichloromethane / 1 h / 20 °C 2: sodium azide / dimethyl sulfoxide / 16.5 h / 0 - 20 °C 3: trifluorormethanesulfonic acid / toluene / 3 h / 20 °C 4: 2,3-dicyano-5,6-dichloro-p-benzoquinone / ethyl acetate / 0.08 h View Scheme

1: sodium azide / dimethyl sulfoxide / 16.5 h / 0 - 20 °C 2: trifluorormethanesulfonic acid / toluene / 3 h / 20 °C 3: 2,3-dicyano-5,6-dichloro-p-benzoquinone / ethyl acetate / 0.08 h View Scheme

1: trifluorormethanesulfonic acid / toluene / 3 h / 20 °C 2: 2,3-dicyano-5,6-dichloro-p-benzoquinone / ethyl acetate / 0.08 h View Scheme

2,3-dicyano-5,6-dichloro-p-benzoquinone in ethyl acetate 0.0833333 h;