tert.-butyl lithium; sodium carbonate 1.) pentane, THF, -70 deg C, 45 min; 2.) -70 deg C, 50 min; 3.) 0 deg C, 10 min; Multistep reaction;

(i) Ni catalyst, (ii) aq. HCl; Multistep reaction;

hydrogenchloride; tert.-butyl lithium 1.) THF, pentane, -70 deg C, 14.5 h; 2.) THF, pentane, -70 deg C, 20 min, then 0 deg C, 20 min; 3) THF, pentane, water 0 deg C, 30 min; Yield given. Multistep reaction. Yields of byproduct given;

zinc in N,N,N',N',N'',N''-hexamethylphosphoric triamide; diethyl ether 0.5 h; Heating;

bromine in dichloromethane