bromine; triethylamine; triphenylphosphine in dichloromethane a) 0.5 h, r.t., b) 12 h, r.t.;

in diethyl ether T=0°C; 2 h;

1: 1) NaH / 1) oil, THF, 0 deg C, 2) THF, 6 h, reflux 2: 93 percent / a) bromine, triphenylphosphine, b) Et3N / CH2Cl2 / a) 0.5 h, r.t., b) 12 h, r.t. View Scheme

1: 78 percent / 10percent aq. NaOH / diethyl ether / 0 deg C, 1 h, then r.t., 1.5 h 2: 1) NaH / 1) oil, THF, 0 deg C, 2) THF, 6 h, reflux 3: 93 percent / a) bromine, triphenylphosphine, b) Et3N / CH2Cl2 / a) 0.5 h, r.t., b) 12 h, r.t. View Scheme

1: 78 percent / 10percent aq. NaOH / diethyl ether / 0 deg C, 1 h, then r.t., 1.5 h 2: 1) NaH / 1) oil, THF, 0 deg C, 2) THF, 6 h, reflux 3: 93 percent / a) bromine, triphenylphosphine, b) Et3N / CH2Cl2 / a) 0.5 h, r.t., b) 12 h, r.t. View Scheme

sodium hydride 1) THF, 2) THF.; Yield given. Multistep reaction;