Palladium-catalyzed cyclization of o-alkynyltrifluoroacetanilides followed by isocyanide insertion: synthesis of 2-substituted 1H-indole-3-carboxamides
A base-controlled synthesis of 2-substituted secondary and tertiary 1H-indole-3-carboxamides through PdCl2-catalyzed cyclization of o-alkynyltrifluoroacetanilides followed by isocyanide insertion has been developed. The reaction proceeds smoothly at ambient temperature using O2 in air as the sole oxidant of the palladium catalyst.
Aminopalladation-Triggered Carbene Insertion Reaction: Synthesis of 2-(1<i>H</i>-Indol-3-yl)acetates
作者:Ziwei Hu、Shuang Luo、Qiang Zhu
DOI:10.1002/adsc.201400799
日期:2015.3.23
red carbeneinsertionreaction for the synthesis of C‐3 alkylated indole derivatives from ortho‐alkynyltrifluoroacetanilides and α‐diazoacetates is presented; it involves a palladium catalyst and a weak base in the open air. Yields range from 49–88% with excellent functional group tolerance. The reaction proceeds through intramolecular aminopalladation of alkynes followed by carbeneinsertion. Migratory
Palladium-Catalyzed Cyclization of <i>N</i>-Acyl-<i>o</i>-alkynylanilines with Isocyanides Involving a 1,3-Acyl Migration: Rapid Access to Functionalized 2-Aminoquinolines
the synthesis of functionalized 2-aminoquinolines via palladium-catalyzed annulation of N-acyl-o-alkynylanilines with isocyanides has been developed with high atom economy, in which an unconventional 6-endo-dig cyclization process is observed. Furtherinvestigations of the mechanism demonstrated that an intramolecular acyl migration of the N-protecting groups was involved in this transformation.
A novel palladium-catalyzed synthesis of free N−H 2,3-disubstituted indoles from arenediazonium tetrafluoroborates and 2-alkynyltrifluoroacetanilides is presented. The reaction tolerates a variety of useful substituents both in the starting alkyne and the arenediazonium salt, including bromo and chloro substituents, nitro, cyano, keto, ester, and ether groups, as well as ortho substituents such as