1: 1.) C2H5MgBr / 1.) THF, reflux, 8 h, 2.) THF, reflux, 8 days 2: CH3MgCl / 1.) THF, 0 deg C, 30 min., 2.) -70 deg C --> room temp., 2.5 h 3: 1.) CuBr, LiBr / 1.) THF, 0 deg C, 2.) -70 deg C --> room temp., 2.5 h View Scheme

1: CH3MgCl / 1.) THF, 0 deg C, 30 min., 2.) -70 deg C --> room temp., 2.5 h 2: 1.) CuBr, LiBr / 1.) THF, 0 deg C, 2.) -70 deg C --> room temp., 2.5 h View Scheme

copper(I) bromide; lithium bromide 1.) THF, 0 deg C, 2.) -70 deg C --> room temp., 2.5 h; Yield given. Multistep reaction;