sodium hydroxide 48 h;

1: 68 percent / N-bromosuccinimide / 2 h / Ambient temperature 2: 74 percent / KO-t-Bu / 2-methyl-propan-2-ol / 0.5 h / Heating 3: 1.) O3, 2.) dimethyl sulfide / 1.) CH2Cl2, -78 deg C, 2.) CH2Cl2, RT, 12 h 4: 1.) KH / 1.) THF, RT, 2.) THF, from -78 deg C to RT 5: 83 percent / aq. NaOH / 48 h View Scheme

1: 74 percent / KO-t-Bu / 2-methyl-propan-2-ol / 0.5 h / Heating 2: 1.) O3, 2.) dimethyl sulfide / 1.) CH2Cl2, -78 deg C, 2.) CH2Cl2, RT, 12 h 3: 1.) KH / 1.) THF, RT, 2.) THF, from -78 deg C to RT 4: 83 percent / aq. NaOH / 48 h View Scheme

1: 1.) KH / 1.) THF, RT, 2.) THF, from -78 deg C to RT 2: 83 percent / aq. NaOH / 48 h View Scheme

1: 1.) O3, 2.) dimethyl sulfide / 1.) CH2Cl2, -78 deg C, 2.) CH2Cl2, RT, 12 h 2: 1.) KH / 1.) THF, RT, 2.) THF, from -78 deg C to RT 3: 83 percent / aq. NaOH / 48 h View Scheme

1: 1.) O3, 2.) dimethylsulphide / 1.) CH2Cl2, -78 deg C 2: 1.) KH / 1.) THF 3: 2 M aq. NaOH View Scheme