Three-Component Friedel-Crafts Reaction of Indoles, Glyoxylate, and Amine under Solvent-Free and Catalyst-Free Conditions - Synthesis of (3-Indolyl)glycine Derivatives - Zhao, Jun-Ling; Liu, Li; Zhang, Hai-Bo; Wu, Yan-Chao; Wang, Dong; Chen, Yong-Jun (Synlett, 2006)