1: 78 percent / Bu3P*CuI / tetrahydrofuran / 1 h / -45 - -35 °C 2: 88 percent / TsOH*H2O / benzene / 6 h / Heating 3: 1) BH3*THF, 2) aq. NaOH, 35percent aq. H2O2 / 1) r.t., 30 min, 2a) < 40 deg C, 2b) 50 deg C, 1 h View Scheme

1: 88 percent / TsOH*H2O / benzene / 6 h / Heating 2: 1) BH3*THF, 2) aq. NaOH, 35percent aq. H2O2 / 1) r.t., 30 min, 2a) < 40 deg C, 2b) 50 deg C, 1 h View Scheme

sodium hydroxide; borane-THF; dihydrogen peroxide 1) r.t., 30 min, 2a) < 40 deg C, 2b) 50 deg C, 1 h; Yield given. Multistep reaction;