LiOtBu-Promoted Synthesis of Bis(3-indolyl)methanes by the Alkylation of Indoles with Alcohols under Air: An Investigation about Mechanism Insights via Chemical Intermediates

Abstract

Abstract Bis(3-indolyl)methanes (BIMs) are known for their important bioactivities, which include anti-cancer, anti-inflammatory, antibacterial, and antioxidant properties. In this study, we are disclosing a metal catalyst-free synthesis of BIMs in high yields via the alkylation reaction of indoles and alcohols in the presence of lithium tert-butoxide base. Notably, oxygen in air played an important role as an oxidant for the facilitation of this transformation. Interestingly, an unactivated aliphatic alcohol (n-hexanol) could be successfully used as an alkylating reagent in the alkylation reaction of indole. Especially, from several chemical intermediates detected by GC-MS gave important information about the mechanism insights. This method demonstrated cost and environmental advantages for the development of green processes.