Graduate School of Pharmaceutical Sciences, Tohoku University , 6-3, Aoba, Aramaki, Aoba-ku, Sendai 980-8578, Japan.
Org Lett. 2012 May 18;14(10):2622-5. doi: 10.1021/ol300958c. Epub 2012 May 7.
In this study, a facile synthesis of 3-carboxylated indoles involving a tandem-type cyclization of 2-ethynylanilines and subsequent CO2 fixation at the 3-position of the indole ring is realized. The reaction proceeds efficiently at 65 °C under 10 atm of CO2, giving rise to variously substituted 3-carboxylated indoles, generally in high yields. An inorganic base, such as K2CO3, is the only reagent required, and the addition of transition metal catalysts is not necessary. The method provides a novel, simple, and promising strategy for CO2 fixation in the research field of heterocyclic chemistry.
在这项研究中，实现了一种简便的 3-羧基吲哚的合成方法，涉及 2-乙炔基苯胺的串联型环化反应，以及随后在吲哚环的 3-位进行 CO2 固定。反应在 65°C 和 10 个大气压的 CO2 下高效进行，生成各种取代的 3-羧基吲哚，通常产率较高。所需的唯一试剂是无机碱，如 K2CO3，而不需要添加过渡金属催化剂。该方法为杂环化学研究领域中的 CO2 固定提供了一种新颖、简单且有前景的策略。
