Department of BioMolecular Sciences, University of Mississippi , University, Mississippi 38677, United States.
J Org Chem. 2017 Feb 17;82(4):2231-2236. doi: 10.1021/acs.joc.6b02863. Epub 2017 Jan 31.
2,2,4,4,4-Pentafluoro-3,3-dihydroxyketones are valuable precursors to difluoroenolates following fragmentation during the release of trifluoroacetate; however, there are few synthetic strategies to prepare this unique class of compound. We addressed this issue and report a mild, two-step synthesis of 2,2,4,4,4-pentafluoro-3,3-dihydroxyketones from aldehydes. Specifically, aldehydes are treated with pentafluoropropen-2-olate, generated from a new fragmentation of hexafluoroisopropanol with a mixed Mg/Li amide, to give pentafluoroalcohols. A subsequent oxidation with Dess-Martin periodinane provides the targets in good isolated yields.
2,2,4,4,4-五氟-3,3-二羟基酮是三氟乙酸酯释放过程中碎裂后得到二氟烯醇盐的有价值前体；然而，很少有合成策略可以制备这种独特的化合物。我们解决了这个问题，并报告了一种从醛制备 2,2,4,4,4-五氟-3,3-二羟基酮的温和的两步合成方法。具体来说，醛与五氟丙烯-2-醇反应，五氟丙烯-2-醇由六氟异丙醇与混合的 Mg/Li 酰胺的新碎裂生成，得到五氟醇。随后用 Dess-Martin 过碘烷氧化得到目标产物，产率良好。
