1: CH2Cl2 / 5 h / Ambient temperature 2: Mg, 1,2-dibromoethane / tetrahydrofuran / Irradiation; 1.) 50 deg C, 45 min then, 2.) 40 deg C, 30 min then room temp. 3: 1.) Br2; 2.) tBuOK / 1.) pentane, -15 deg C; 2.) 0 deg C, 120 min 4: 92 percent / NaNH2 in liq NH3 / pentane; diethyl ether / 0.3 h 5: 59 percent / HgSO4, 6NH2SO4 / diethyl ether; pentane / 2.75 h / Ambient temperature View Scheme

potassium carbonate 30 h; Heating; Yield given. Title compound not separated from byproducts;

1: CH2Cl2 / 5 h / Ambient temperature 2: 90 percent / KOtBu / pentane / 2 h / Ambient temperature View Scheme

1: CH2Cl2 / 5 h / Ambient temperature 2: Mg, 1,2-dibromoethane / tetrahydrofuran / Irradiation; 1.) 50 deg C, 45 min then, 2.) 40 deg C, 30 min then room temp. 3: 1.) Br2; 2.) tBuOK / 1.) pentane, -15 deg C; 2.) 0 deg C, 120 min View Scheme

1: CH2Cl2 / 5 h / Ambient temperature 2: Mg, 1,2-dibromoethane / tetrahydrofuran / Irradiation; 1.) 50 deg C, 45 min then, 2.) 40 deg C, 30 min then room temp. 3: 1.) Br2; 2.) tBuOK / 1.) pentane, -15 deg C; 2.) 0 deg C, 120 min 4: 92 percent / NaNH2 in liq NH3 / pentane; diethyl ether / 0.3 h View Scheme

2,2,2-trichlorobenzo[d]-1,3,2λ5-dioxaphosphole in dichloromethane 5 h; Ambient temperature;

in dichloromethane 5 h; Ambient temperature;