Triflic Acid as an Efficient Brønsted Acid Promoter for the Umpolung of N-Ac Indoles in Hydroarylation Reactions
作者:Raj Kumar Nandi、Alejandro Perez-Luna、Didier Gori、Rodolphe Beaud、Régis Guillot、Cyrille Kouklovsky、Vincent Gandon、Guillaume Vincent
DOI:10.1002/adsc.201701074
日期:2018.1.4
We report that triflicacid, a strong Brønsted acid, is a very powerful alternative to FeCl3 to mediate the hydroarylation of N−Ac indoles, which delivers regioselectively 3‐arylindolines, 3,3‐spiroindolines or 2‐arylindolines. Mechanistic explorations point towards the existence of a highly electrophilic intermediate by simultaneous activation of the acetyl and of the C2=C3 bond by protons.
The puzzling hydroarylation of N-Ac indoles promoted by iron trichloride involves a doubly activated intermediate: as supported by the electron density topology of a crystal, IR monitoring, and DFT calculations.
Regioselective Hydroarylation Reactions of C3 Electrophilic<i>N</i>-Acetylindoles Activated by FeCl<sub>3</sub>: An Entry to 3-(Hetero)arylindolines
作者:Rodolphe Beaud、Régis Guillot、Cyrille Kouklovsky、Guillaume Vincent
DOI:10.1002/chem.201400284
日期:2014.6.10
indole nucleus to generate a quaternary center at C3 and leads regioselectively to 3‐arylindolines. Optimization, scope (50 examples), practicability (gram scale, air atmosphere, room temperature), and mechanisticinsights of this process are presented. Synthetic transformations of the indoline products into drug‐like compounds are also described.