A highly active catalyst for the reductive cyclization of ortho-nitrostyrenes under mild conditions
作者:Ian W. Davies、Jacqueline H. Smitrovich、Rick Sidler、Chuanxing Qu、Venita Gresham、Charles Bazaral
DOI:10.1016/j.tet.2005.03.142
日期:2005.6
A mild and efficient method for the palladium-Catalyzed reductive Cyclization of ortho-nitrostyrenes to afford indoles is reported. \Treatment of ortho-nitrostyrenes with 0.1 mol% palladium (II) trifluoracetate [Pd(TFA)(2)] and 0.7 mol% 3.4,7,8-tetramethyl-1,10-phenanthroline (tm-phen) in DMF at 15 psig CO and 80 degrees C afforded indoles in good to excellent yields. When the reaction was conducted in toluene. the corresponding N-hydroxyindole was isolated. A mechanism that accounts for the formation of N-hydroxyindole is proposed. (c) 2005 Elsevier Ltd. All rights reserved.