Saito Akio, Oda Shoko, Fukaya Haruhiko, Hanzawa Yuji
Laboratory of Organic Reaction Chemistry, Showa Pharmaceutical University, 3-3165 Higashi-Tamagawagakuen, Machida, Tokyo 194-8543, Japan.
J Org Chem. 2009 Feb 20;74(4):1517-24. doi: 10.1021/jo8022523.
Mild and facile preparations of 2-substituted or 2,3-disubstituted indole compounds were achieved by RhH(CO)(Ph(3)P)(3) (4-10 mol %)-catalyzed reaction of N-propargylanilines in hexafluoroisopropyl alcohol (HFIP). The formation of indoles was proven to be derived from an o-allenylaniline intermediate, which was generated by the Rh(I)-catalyzed amino-Claisen rearrangement of N-propargylanilines. The catalytic system is also available for the one-pot synthesis of indoles by reacting N-alkylaniline (1 equiv) with propargyl bromide (1.3 equiv) in the presence of K(2)CO(3) (3 equiv) in HFIP. The active catalyst was proven to be [Rh(CO)(Ph(3)P)(2)]OCH(CF(3))(2) generated in situ from RhH(CO)(Ph(3)P)(3) and HFIP. The structure of [Rh(CO)(Ph(3)P)(2)]OCH(CF(3))(2) was confirmed by single-crystal X-ray crystallographic analysis.
通过RhH(CO)(Ph(3)P)(3)（4 - 10 mol%）催化N-炔丙基苯胺在六氟异丙醇（HFIP）中的反应，实现了2-取代或2,3-二取代吲哚化合物的温和简便制备。吲哚的形成被证明源自邻烯丙基苯胺中间体，该中间体是由Rh(I)催化的N-炔丙基苯胺的氨基克莱森重排产生的。该催化体系也可用于在HFIP中，在K(2)CO(3)（3 equiv）存在下，使N-烷基苯胺（1 equiv）与炔丙基溴（1.3 equiv）反应一锅法合成吲哚。活性催化剂被证明是由RhH(CO)(Ph(3)P)(3)和HFIP原位生成的[Rh(CO)(Ph(3)P)(2)]OCH(CF(3))(2)。通过单晶X射线晶体学分析确定了[Rh(CO)(Ph(3)P)(2)]OCH(CF(3))(2)的结构。
