1: 3,5-difluoropyridine With lithium diisopropyl amide in tetrahydrofuran T=-72 - -69°C; 0.5 h; 2: With chloro-trimethyl-silane in tetrahydrofuran 3: methoxyacetic acid methyl ester With ammonium chloride; lithium diisopropyl amide more than 3 stages;