溴水催化还原的α,α,α-三溴甲基酮类化合物的高选择性控制脱溴反应研究

Study on Highly Selective Control of Debromination Reaction of α,α,α-Tribromomethyl Ketones Catalyzed by Bromine Water

摘要: 以1,4-二氧六环为溶剂，通过调节溴水溶液的质量和反应温度，实现了α,α,α-三溴甲基酮的高选择性还原脱溴。以中等至良好的收率合成了α,α-二溴甲基酮和α-一溴甲基酮。该反应具有广泛的底物和官能团耐受性，为α,α-二溴甲基酮和α-单溴甲基酮衍生物的合成提供了新途径。以α,α,α-三溴甲基酮(0.1 mmol)为反应底物，在80℃下1,4-二氧六环溶剂中加入20 mg溴水(Br₂ (3.2 mg)，H₂O (16.8 mg))作为还原剂可得到产率为86%的α,α-二溴甲基酮。在α,α,α-三溴甲基酮类化合物的单次脱溴反应中，发现反应温度和溴水质量对α-一溴甲基酮的合成产生重大影响。因此，在本实验中，我们不断调整溴水的质量，调整反应温度，实现选择性合成α-一溴甲基酮。以α,α,α-三溴甲基酮(0.1 mmol)为原料，30 mg溴水(Br₂ (4.8 mg)，H₂O (25.2 mg))为催化剂，温度120℃，在1,4-二氧六环溶剂中可得到收率77%的α-一溴甲基酮。

Abstract: Using 1,4-dioxane or tetrahydrofuran as a solvent, the highly selective reductive debromination of α,α,α-tribromomethyl ketones was achieved by adjusting the quality of bromine water solution and reaction temperature. The α,α-dibromomethyl ketones, α-monobromomethyl ketones, and methyl ketones with moderate to good yields were synthesized. This reaction has a wide range of substrates and functional group tolerance, providing a new pathway for the synthesis of α,α-dibromomethyl ketone, α-monobromomethyl ketone methyl ketone derivatives. With α,α,α-Tribromomethyl ketone (0.1 mmol) was used as the reaction substrate, and 20 mg of bromine water (Br₂ (3.2 mg), H₂O (16.8 mg)) was added to 1,4-dioxane solvent at 80˚C as the reducing agent to obtain a product with a yield of 86% α,α-Dibromomethyl ketone. In the single debromination reaction of tribromomethyl ketone compounds, it was found that the reaction temperature and the quality of bromine water were important to the synthesis of α-bromomethyl ketone and have a significant impact. The synthesis of Dibromomethyl ketones can have a significant impact. Therefore, in this experiment, we constantly adjust the quality of bromine water, adjust the reaction temperature, and realize selective synthesis α-Bromomethyl ketone. With α,α,α-tribromophenone (0.1 mmol) as the raw material, 30 mg of bromine aqueous solution, Br₂ (4.8 mg) as a catalyst, H₂O (25.2 mg)), the temperature being 120˚C, a 77% yield can be obtained within a 1,4-dioxane solvent α-Monobromomethyl ketone.