Reversed-Polarity Synthesis of Diaryl Ketones through Palladium-Catalyzed Direct Arylation of 2-Aryl-1,3-dithianes
作者:Baris Yucel、Patrick J. Walsh
DOI:10.1002/adsc.201400695
日期:2014.11.24
resulting 2,2-diaryl-1,3-dithianes were converted into diaryl ketones by either molecular iodine, N-bromo succinimide (NBS) or Selectfluor in the presence of water. The dithiane arylation/hydrolysis can be performed in a one-pot procedure to yield a good to excellent yields. This method is suitable for rapid and large-scale synthesis of diaryl ketones. A one-pot preparation of anti-cholesterol drug fenofibrate
基于酰基阴离子等价物的原位生成及其催化芳基化,开发了一种合成二芳基酮的umpolung方法。该方法需要碱促进的钯催化 2 与芳基溴直接进行 CH 芳基化,得到 2,2-二芳基-1,3-二噻烷。使用 MN(SiMe3)2 (M=Li, Na) 碱会导致弱酸性二噻烷的可逆去质子化。在 Pd(NiXantphos) 基催化剂和芳基溴存在下,金属化 2-芳基-1,3-二噻烷在温和条件下(室温下 2 小时)发生交叉偶联,产率高达 96%。所得的 2,2-二芳基-1,3-二噻烷在水存在下通过分子碘、N-溴琥珀酰亚胺 (NBS) 或 Selectflu 转化为二芳基酮。二噻烷芳基化/水解可以在一锅法中进行,以获得良好至优异的产率。该方法适合二芳基酮的快速、大规模合成。已经实现了10.0 mmol规模的一锅法制备抗胆固醇药物非诺贝特(TriCor(R)),收率86%。