通过硅基烯醇醚实现酮的α-三氟甲基化的机理研究及其在其他羰基化合物中的应用。

Mechanistic studies on alpha-trifluoromethylation of ketones via silyl enol ethers and its application to other carbonyl compounds.

作者信息

Sato Kazuyuki, Yuki Takashi, Yamaguchi Ryoji, Hamano Tetsuya, Tarui Atsushi, Omote Masaaki, Kumadaki Itsumaro, Ando Akira

机构信息

Faculty of Pharmaceutical Sciences, Setsunan University, 45-1, Nagaotoge-cho, Hirakata, Osaka 573-0101, Japan.

出版信息

J Org Chem. 2009 May 15;74(10):3815-9. doi: 10.1021/jo9004348.

DOI:10.1021/jo9004348

PMID:19366204

Abstract

Synthesis of alpha-CF(3) carbonyl compounds has been recognized to be difficult up to now because the polarization of CF(3)(delta-)-I(delta+) is opposite to that of CH(3)(delta+)-I(delta-), and this makes it difficult to introduce CF(3)(+) unit to enolates. We recently reported an effective alpha-trifluoromethylation of ketones by using Et(2)Zn with Rh catalyst, but the mechanism has not fully been cleared. Now, we carried out the detailed mechanistic studies and found the involvement of a highly reactive alkylrhodium complex which derived from Et(2)Zn and RhCl(PPh(3))(3) in this alpha-trifluoromethylation. Furthermore, this alpha-trifluoromethylation was applied to other types of carbonyl compounds in good yields.

摘要

迄今为止，α-三氟甲基羰基化合物的合成一直被认为是困难的，因为CF(3)(δ-)-I(δ+)的极化与CH(3)(δ+)-I(δ-)相反，这使得将CF(3)(+)单元引入烯醇盐变得困难。我们最近报道了使用Et(2)Zn与Rh催化剂对酮进行有效的α-三氟甲基化反应，但该反应机理尚未完全明确。现在，我们进行了详细的机理研究，发现在该α-三氟甲基化反应中涉及一种由Et(2)Zn和RhCl(PPh(3))(3)衍生的高活性烷基铑配合物。此外，这种α-三氟甲基化反应以良好的产率应用于其他类型的羰基化合物。