n-butyllithium 1) dimethoxyethane, -60 deg C, 10 min, 2) -60 deg C, 1.5 h, warm to r.t.; Yield given. Multistep reaction;

n-butyllithium 1) dimethoxyethane, -60 deg C, 10 min, 2) -60 deg C, 1.5 h, warm to r.t.; Yield given. Multistep reaction. Yields of byproduct given;