1: 86 percent / iPr2NEt / CH2Cl2 / 1.5 h 2: 53 percent / Pd(dba)2, AsPh3, NMP / 4 h / 100 °C 3: 88 percent / H2SO4 / methanol; tetrahydrofuran / 0.75 h / Ambient temperature View Scheme

1: 86 percent / iPr2NEt / CH2Cl2 / 1.5 h 2: 53 percent / Pd(dba)2, AsPh3, NMP / 4 h / 100 °C 3: 88 percent / H2SO4 / methanol; tetrahydrofuran / 0.75 h / Ambient temperature 4: 85 percent / LiOH*H2O / tetrahydrofuran / 3 h / Ambient temperature View Scheme