1: acetoacetic acid benzyl ester With n-butyllithium; diisopropylamine in tetrahydrofuran; hexane T=0°C; 1 h; 2: n-amyl iodide in tetrahydrofuran T=0 - 20°C; 2 h;

in N,N-dimethyl-formamide 17 h; Ambient temperature;

1: 1.) 1.6 M n-butyllithium / 1.) hexane, THF, r.t., 2 h; 2.) 60 deg C, 2 h 2: hexane; tetrahydrofuran; dimethylformamide / 3 h / Ambient temperature View Scheme

1: oxalyl chloride / CHCl3 / Ambient temperature 2: tetrahydrofuran; H2O / 0.5 h / Ambient temperature 3: 1.) 1.6 M butyllithium / 1.) hexane, THF, -78 deg C, 10 min; 2.) 30 min 4: 1.) 1.6 M n-butyllithium / 1.) hexane, THF, r.t., 2 h; 2.) 60 deg C, 2 h 5: hexane; tetrahydrofuran; dimethylformamide / 3 h / Ambient temperature View Scheme

1: tetrahydrofuran; H2O / 0.5 h / Ambient temperature 2: 1.) 1.6 M butyllithium / 1.) hexane, THF, -78 deg C, 10 min; 2.) 30 min 3: 1.) 1.6 M n-butyllithium / 1.) hexane, THF, r.t., 2 h; 2.) 60 deg C, 2 h 4: hexane; tetrahydrofuran; dimethylformamide / 3 h / Ambient temperature View Scheme

1: 1.) 1.6 M butyllithium / 1.) THF, hexane, -78 deg C, 15 min; 2.) THF, allowed to r.t. during 30 min 2: 1.) 1.6 M n-butyllithium / 1.) hexane, THF, r.t., 2 h; 2.) 60 deg C, 2 h 3: hexane; tetrahydrofuran; dimethylformamide / 3 h / Ambient temperature View Scheme

1: 1.) 1.6 M butyllithium / 1.) hexane, THF, -78 deg C, 10 min; 2.) 30 min 2: 1.) 1.6 M n-butyllithium / 1.) hexane, THF, r.t., 2 h; 2.) 60 deg C, 2 h 3: hexane; tetrahydrofuran; dimethylformamide / 3 h / Ambient temperature View Scheme

in benzene