A new efficient strategy for the synthesis of 3‐trifluoromethyl‐indoles was developed through tandemcyclization/trifluoromethylation of 2‐alkynylanilines and Umemoto's reagent under effect of CuBr. The reaction features the use of cheap copper salt, mild reaction conditions and high yield of products. The preliminary mechanism study indicates the solvent dimethylacetamide acts as the role of dealkylation
Herein, we demonstrated that 2-alkynyldimethylamines easily cyclize in EtOH according to a 5-endo-dig annulation into 2-substitutedindoles without the aid of any additives or any metal catalysts to activate the triple bond. Thus, a variety of functionalized 2-styrylindoles, 2-arylindoles, 2-alkynylindoles, and 2-alkylindoles were prepared in high to excellent yields according to an environmentally
A visible-light photoredox synthesis of 3-acylindoles through intramolecular oxidative cyclization of o-alkynylated N,N-dialkylamines is developed. The reaction proceeds effectively under mild reaction conditions using air as the oxidant, and only water is generated as a side product. A plausible mechanism involving the addition of α-amino alkyl radicals to alkynes, followed by C–O bond formation,
A new synthesis of indoles via intramolecular cyclization of ο-alkynyl N,N-dialkylanilines promoted by KOt-Bu/DMSO
作者:Yan-yan Chen、Jia-hua Chen、Niu-niu Zhang、Lin-miao Ye、Xue-Jing Zhang、Ming Yan
DOI:10.1016/j.tetlet.2014.12.002
日期:2015.1
2-Aryl indoles could be prepared in excellent yields via the intramolecular cyclization of o-alkynyl N,N-dialkylanilines. The reaction is efficiently promoted by the catalytic amount of KOr-Bu in DMSO at room temperature. A reaction mechanism involving alpha-aminoalkyl radical intermediates is suggested. (C) 2012 Elsevier Ltd. All rights reserved.