FeCl3·6H2O as a Mild Catalyst for Nucleophilic Substitution of Symmetrical Bis(indoyl)methanes

In this paper, unsymmetrical bis­(indolyl)­methane (BIM) and 3-alkylindole derivatives are smoothly synthesized from symmetrical BIMs with a variety of nucleophiles including heteroaromatic/aromatic compounds, allylsilane and alkynylsilane. FeCl3·6H2O is found to be a mild and highly effective catalyst for this nucleophilic substitution reaction in which N-methyl-2-phenylindole behaves as a good leaving group in the Csp3 –Csp2 bond cleavage reaction. The operational ease, nonexpensive and environmentally friendly catalyst, mild reaction conditions, broad functional group tolerance, and scalability of this reaction strategy are advantages of the present procedure.