A new procedure for the synthesis of 2-(2-indolyl)pyrroles, 2,3′-bi-indolyls, and 2-(3-indolyl)-3-(2-indolyl)indoles

The 3-bromoindoles were found to react with pyrroles and indoles, in the presence of protic or Lewis acids, to give 2-(2-indolyl)pyrroles, 2,3′-bi-indolyls, and trimetic products such as 2-(3-indolyl)-3-(2-indolyl)indoles.