1: 77 percent / 10percent aq.KOH, TEBA / CH2Cl2 / 0.67 h 2: 95 percent / DMSeO / 1,2-dichloro-ethane / 3.5 h / Heating 3: 70 percent / NaOH, TEBA / tetrahydrofuran / 4 h / Ambient temperature 4: 79 percent / silver(II) dipicolinate / benzene; H2O / Ambient temperature View Scheme