A facile synthesis of 4-gem-difluoromethylene β-lactam and its derivatives from BrCF2CF2Br

4-Bromodifluoromethyl β-lactams 2 are prepared from the commercial available BrCF2CF2Br in overall five-step reaction procedure. Under the radical reaction conditions (Bu3SnH/AIBN), compound 2 reacted with alkenes affording to the corresponding addition product difluoromethylene β-lactams 7. In the absence of alkenes, it can be converted into the corresponding difluoromethyl β-lactam 6 in almost quantitative yield. Furthermore, allylic stannic reagent Bu3SnCH2CHCH2 reacted with 2 under the same reaction conditions gave the allylic addition product 8.