Synthesis of tris(indolyl)methanes by using dimethyl carbonate as a single carbon source via C-H functionalization approach

Here, we report a copper acetate/tert-butyl hydroperoxide-mediated reaction of N-substituted indoles with dimethyl carbonate under heating to give tris(indolyl)methanes via alpha-C-H functionalization of the methoxy group of dimethyl carbonate. The central methine carbon in the product comes from the dimethyl carbonate molecule, which is used as a substrate as well as a reaction medium. The reaction uses a cheap and environmentally benign copper metal catalyst which makes the process useful. This is the first report of tris(indolyl)methane synthesis using dimethyl carbonate as a single carbon source.