反应条件
1: 3,4-difluoro-benzoic acid With N,N,N',N,-tetramethylethylenediamine; sec.-butyllithium in tetrahydrofuran; cyclohexane T=-78°C; 1 h; 2: 1,2,2-trichloro-1,1,2-trichloro-ethane in tetrahydrofuran; cyclohexane T=-78 - 20°C; 1 h; 3: With water in tetrahydrofuran; cyclohexane