Photocatalyst-free visible light driven synthesis of gem -dihaloenones from alkynes, tetrahalomethanes and water.

Photocatalytic reactions, in particular, processes without photosensitisers, have attracted increased attention due to their green aspect and high economic value and are considered valuable tools in organic synthesis. A new practical photocatalytic system was investigated in this study, and it can efficiently produce gem -dihaloenones by combining terminal alkynes with tetrahalomethanes (BrCCl 3 and CBr 4 ) and water without a photocatalyst, and the yield can reach up to 87%. The catalytic system is straightforward, the raw materials are inexpensive and easy to obtain, and the operation is simple.