1: aq. KOH / dimethylsulfoxide / 48 h / 90 °C 2: (i) PCl5, Et2O, (ii) liq. NH3, bis-(2,3-dimethyl-propyl)-borane, THF, (iii) aq. H2O2 3: 2,2,2-trichloro-<1,3,2>benzodioxaphospholane / 100 °C 4: 4 h / 130 °C View Scheme

1: aq. KOH / dimethylsulfoxide / 48 h / 90 °C 2: (i) PCl5, Et2O, (ii) liq. NH3, bis-(2,3-dimethyl-propyl)-borane, THF, (iii) aq. H2O2 3: 2,2,2-trichloro-<1,3,2>benzodioxaphospholane / 100 °C 4: 4 h / 130 °C View Scheme