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Solvent 2a Yield 3a Yield [%] [b] [%] [b] 1H 2 SO 4 CH 3 CN no no 2 HNO 3 CH 3 CN no no 3CH 3 COOH CH 3 CN 5 0 4 PhCOOH CH 3 CN 6 0 5 p-CH 3 C 6 H 4 SO 3 HCH 3 CN 5 0 6 HCl CH 3 CN 5 0 7HI CH 3 CN 15 0 8 HBr CH 3 CN 76 0 9 HBr AcOEt 82 0 10 HBr DCE 7 0 11 HBr toluene 29 0 12 HBr EtOH 55 0 13 HBr THF 92 0 14 [c] HBr THF 81 0 15 [d] HBr THF 80 0 16 [e] HBr THF 82 0 17 [f] HBr THF 70 0 18 [g] HBr THF 085 19 [h] HBr THF 15 66 20 - THF 0 0 [a] The reactions of 1a (0.10 mmol) and H + (0.10 mmol) were carried out in 1 mL of solvent at 80 °C for 10 h. [b] Isolated yield. It is noteworthy that the Br 2 produced in the reaction system would react well with water to generate HBr, which would be capable of catalyzing another round of reaction. Communication doi.org/10.1002/ejoc.202001118 EurJOC European Journal of Organic Chemistry Debromination Selective Debromination of , , -Tribromomethylketones with HBr-H 2 O Reductive Catalytic System Hui Wang, [a][‡] Meng-Xia Zheng, [a][‡] Hongmei Guo, [b] Guozheng Huang, [b] Zhao Cheng,* [c] and Abulikemu Abudu Rexit* [a] Abstract: A debromination of , , -tribromomethylketones is developed for chemoselective synthesis of -mono- and , dibromomethylketones with high selectivity under H 2 O-HBr reductive conditions. Interestingly, hypobromic acid would also decompose at high temperatures and generate another of HBr, which ensured that a sufficient amount of HBr to support multiple rounds of HBr-H 2 O reduction. [Extracted from the article]