1: (3-bromo-3,3-difluoroprop-1-ynyl)(triisopropyl)silane With indium in tetrahydrofuran; water T=20°C; Metallation; 2: formaldehyd in tetrahydrofuran; water T=20°C; Addition; 12 h; Further stages.;

1: (3-bromo-3,3-difluoroprop-1-ynyl)(triisopropyl)silane With indium in tetrahydrofuran; water T=5°C; 8 h; sonication; 2: formaldehyd in tetrahydrofuran; water 17 h; sonication;

1: With indium; ammonium chloride in tetrahydrofuran sonication; 2: With bromine in tetrahydrofuran T=-78 - -20°C;