development of new amide precursors for selective, catalytic activation of carbon–nitrogen bonds in amides is a fundamental objective of this emerging reactivity manifold. We report the palladium-catalyzed Suzuki–Miyauracross-coupling of N-acylcarbazoles and N-acylindoles with arylboronicacids by a highly selective N–C(O) cleavage. The key amide bond ground-state destabilization stems from Nlp to Ar conjugation
N-Acylation of 5-Substituted Indoles with Carboxylic Acids via DCC Coupling
作者:John B. Bremner、Siritron Samosorn、Joseph I. Ambrus
DOI:10.1055/s-2004-831228
日期:——
A method for the N-acylation of 5-substituted indoles with carboxylic acids using DCC and DMAP is presented. High yields were obtained when an electron-withdrawing group was present at C-5, however the method was less effective with a C-5 electron-donating group.
Stable and easily accessible N-aroylbenzotriazoles react with indoles in the presence of a base to afford the corresponding N-aroylindoles in yields averaging 70%. This method is effective even when both coupling reagents possess electron-donating substituents.
Nickel-catalyzed decarbonylation of N-acylated N-heteroarenes is developed. This method can be used to produce a variety of N-aryl heteroarenes, including pyrroles, indoles, carbazoles and phenoxazines, using benzoic acid derivatives as arylating reagents. Arylnickelamide intermediates that are relevant to the catalytic reaction were characterized by X-ray crystallography. When N-acylated benzimidazoles
开发了镍催化的N-酰化 N-杂芳烃的脱羰。该方法可用于生产多种N-芳基杂芳烃,包括吡咯、吲哚、咔唑和吩恶嗪,使用苯甲酸衍生物作为芳基化试剂。与催化反应相关的芳基镍酰胺中间体通过 X 射线晶体学进行了表征。当N-酰化苯并咪唑用作底物时,脱羰伴随1,2-迁移形成2-芳基化苯并咪唑。
A New Approach to Pyrrolophenanthridone Alkaloids via Intramolecular Radical Cyclization
作者:Otohiko Tsuge、Taizo Hatta、Hiroshi Tsuchiyama
DOI:10.1246/cl.1998.155
日期:1998.2
A newapproach to the synthesis of pyrrolophenanthridone class of alkaloids is described. The method is based on intramolecular radicalcyclization of easily accessible 1-aroyl-7-bromoindoles with Bu3SnH and AIBN.