C7-Friedel-Crafts alkylation of 4-aminoindoles with para-quinone methide derivatives under catalyst-free conditions

The first example of Friedel-Crafts alkylation of indoles with para-quinone methide derivatives at the C7 position was developed by using 4-alkylaminoindoles as nucleophiles under catalyst-free conditions. It is a mild and efficient protocol to access 7-indolyl-containing triarylmethane derivatives. This methodology features advantages including broad scope, operational simplicity, and the potential utility for the synthesis of biologically active compounds.