One-Pot Synthesis of Fused Unsymmetrical 2,2′-Biindolyls

Significance

A concise synthesis of fused ­unsymmetrical 2,2′-biindolyl derivatives 3 is ­presented. In this one-pot process, dibromovinyl substrates 1, which are easily prepared from o-gem-dibromovinylanilines and indole-1-carboxylic acids, initially undergo intramolecular C-N coupling to form the indole derivative 2 which, upon intramolecular direct C-H activation/C-C coupling, afford the unsymmetrical 2,2′-biindolyl derivatives 3 in moderate to good yields. The pyrrole derivative of 1 also smoothly undergoes the one-pot process to attain the analogous indole-pyrrole 2,2′-biheterocycle. Overall, the reaction scope was not well investigated.