Abstract
Here, we have developed a 3-component one-pot sequential approach to 3-substituted indoles. The main advantages of this process are step economy, reduced waste, and operational simplicity. The method involves in situ generation of 3-indolylalcohols from the reaction of indoles and aldehydes in the presence of base. Further, nucleophilic substitution of 3-indolylalcohols with various nucleophiles affords 3-substituted indole derivatives. The reaction does not requires any hazardous and expensive metal catalyst. In addition, the reaction is carried out in (1:1) ethanol–water which is considered as environmentally benign solvent. On the other hand, nonsequential 3-component reaction results in the formation of unwanted bisindolylmethanes.
Graphical Abstract
![](/cms/asset/c69d9558-a582-47a7-9039-640527ebe47d/lsyc_a_1482352_uf0001_c.jpg)
Acknowledgements
We acknowledge Dr. S. Karmakar for collecting single-crystal X-ray data and the Sophisticated Analytical Instrumentation Facility (SAIF), Gauhati University, for use of the single-crystal X-ray diffractometer. We acknowledge Gauhati University, Indian Institute of Technology, Guwahati and National Chemical Laboratory, Pune for the NMR and Mass spectral facility.