Highly efficient and recyclable catalyst for the direct chlorination, bromination and iodination of terminal alkynes

- Versatile halogenation method for terminal alkynes is proposed.
- 39 successful examples vary from chlorination, bromination to iodination are presented, up to 99% yields.
- Catalyst is recyclable, 99% yield achieved even after 5 runs.
- Mild reaction conditions.

Direct halogenation, including chlorination, bromination and iodination of terminal alkynes, are of great importance in organic synthesis. Here an efficient and recyclable nano-Ag/g-C3N4 catalyst system was developed and proved to be remarkably active with 39 examples varied from chlorination, bromination to iodination, of which 14 runs have yielded more than 95% of the product. Recycling of the catalyst was also achieved without obvious activity loss after several runs: 99% yield was observed even after 5 runs in the bromination of phenylacetylene. The catalysts system is of low cost and easy to be prepared, making this procedure versatile, convenient and economic.

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