n-butyllithium; N,N-dimethyl-formamide 1.) THF, hexane, -75 deg C, 30 min, 2.) THF, hexane, a.) -75 deg C, 1 h, b.) -30 deg C, 1 h, c.) 0 deg C, 1 h; Yield given. Multistep reaction. Yields of byproduct given;

methyl lithium LiBr complex; water 1.) THF, ether, -75 deg C, 3 h; Yield given. Multistep reaction. Yields of byproduct given;

1.) THF, hexane, -75 deg C, 30 min, 2.) THF, hexane, a.) -75 deg C, 1 h, b.) -30 deg C, 1 h, c.) 0 deg C, 1 h; Yield given. Multistep reaction. Yields of byproduct given;

methyl lithium LiBr complex; water 1.) THF, ether, -75 deg C, 3 h; Yield given. Multistep reaction. Yields of byproduct given;

1: 73 percent / m-CPBA / CH2Cl2 / 24 h / Ambient temperature 2: 92 percent / POCl3 / CHCl3 / 1 h / Heating View Scheme