對烯烴或炔烴的加成，是合成氟代烴最直接的方法。由於F2和HF的使用不便以及反應放熱嚴重，難以控制，限制了其在有機合成中的應用，但在工業上應用較多。
而單氟代烷烴則是通過HF對烯烴的加成製備，反應遵循Markovnikov規則。由於操作和控制不方便，一個替代方法是使用Olah試劑（HF/Pyridine）。
同樣，Olah試劑對炔烴的加成則生成二氟代烷烴。
AcOF，CF3OF，FOClO3，和CsSO4F等試劑對烯烴的加成會引入另一個官能團，得到鄰位取代的氟化物。
NO2BF4對烯烴加成得到鄰硝基氟化物，引入一個含氮官能團。
鄰滷氟化物可以通過不同試劑對烯烴的加成製得，如環己烯，在不同的條件下生成鄰氯，鄰溴和鄰碘的氟代環己烷。
1-Bromo-2-fluoro-2-phenylpropane. A magnetically stirred mixture of α-methylstyrene (7.1 g, 60 mmol), triethylamine trihydrofluoride and (14.7 mL, 90 mmol) and dichloro- methane (60 mL) contained in a 250 mL, single-necked, round-bottomed flask is treated with N-bromosuccinimide (11.8 g, 66 mmol) at 0°C. After 15 min, the bath is removed, and stirring is continued at room temperature for 5 hr. The reaction mixture is poured into ice water (1000 mL), made slightly basic with aqueous 28% ammonia, and extracted with dichloromethane (4 × 150 mL). The combined extracts are washed with 0.1 N hydrochloric acid (2 × 150 mL) and 5% sodium hydrogen carbonate solution (2 × 150 mL) and then dried over magnesium sulfate . After removal of the solvent by rotary evaporation, the crude product is distilled to give the product: 11.6 g (89%); bp 50-52°C(0.15 mm), n20 D1.5370.
來源：凌凱醫藥