Synthesis of 2-amino-3-arylindoles and their Fused Analogues via Intramolecular C-Arylation

Abstract

2-Aminobenzyl cyanide was reacted with nitrobenzenesulfonyl chlorides and alkylated under Mitsunobu or Fukuyama conditions. The resulting intermediates were exposed to basic conditions, which triggered a Truce-Smiles rearrangement, leading to intramolecular C-arylation. This reaction was followed by spontaneous cycloaddition, which yielded 2-aminoindole derivatives. The developed synthetic route represents a metal-free approach for accessing 1-substituted 2-amino-3-arylindoles. Furthermore, pyrimido[1,2-a]indoles and 7,8dihydrobenzo[6,7][1,3]diazepino[4,5-b]indoles were synthesized through the use of functionalized alcohols.