State Key Laboratory and Institute of Elemento-Organic Chemistry, College of Chemistry, Nankai University, Tianjin, 300071, China.
Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin, 300071, China.
Chem Asian J. 2018 Sep 17;13(18):2664-2670. doi: 10.1002/asia.201800766. Epub 2018 Aug 1.
A straightforward Lewis acid-promoted protocol for 3,3'-bisindolylmethanes (BIMs) synthesis by reductive alkylation of indoles at the C3 position with carboxylic acids in the presence of hydrosilane was developed for the first time. Instead of aldehydes, more readily available, stable, and easy-to-handle carboxylic acids have been employed as alternative alkylating agents. As an efficient organocatalyst, B(C F ) enables the reductive alkylation of various substituted indole derivatives with carboxylic acids with up to 98 % yield at room temperature and under neat conditions. This metal-free strategy offers an alternative approach for the direct functionalization of indoles to BIMs with carboxylic acids and such protocol allows selective reduction of carboxylic acid to aldehyde in combination with C-C bond formation.
首次开发了一种通过在硅烷存在下用羧酸对吲哚 C3 位进行还原烷基化反应来合成 3,3'-双吲哚甲烷（BIMs）的直链路易斯酸促进的方法。该方法选用了更易得、更稳定、更易于处理的羧酸代替醛作为替代烷基化试剂。作为一种有效的有机催化剂，B(CF3)5 能够使各种取代的吲哚衍生物与羧酸在室温下、在无金属条件下以高达 98%的产率进行还原烷基化反应。这种无金属策略为羧酸直接官能化吲哚生成 BIMs 提供了一种替代方法，并且该方法还允许在形成 C-C 键的同时选择性地将羧酸还原为醛。
