Synthesis of diverse indole libraries on polystyrene resin - Scope and limitations of an organometallic reaction on solid supports

Applications of Bartoli indole synthesis

In 1989, the reaction of vinyl magnesium halides with ortho-substituted nitroarenes leading to indoles was discovered. This reaction is now frequently reported as the "Bartoli reaction" or the "Bartoli indole synthesis" (BIS). It has rapidly become the shortest and most flexible route to 7-substituted indoles, because the classical indole syntheses generally fail in their preparation. The flexibility of the Bartoli reaction is great as it can be extended to heteroaromatic nitro derivatives and can be run on solid support. This review will focus on the use of the Bartoli indole synthesis as the key step in preparations of complex indoles, which appeared in the literature in the last few years.

Solid-phase synthesis of 2-aryl-3-alkylamino-1H-indoles from 2-nitro-N-(2-oxo-2-arylethyl)benzenesulfonamides via base-mediated C-arylation

Polymer-supported 2-nitro-N-(2-oxo-2-arylethyl)benzenesulfonamides, prepared from resin-bound amines by sulfonylation with 2-nitrobenzenesulfonyl chlorides followed by alkylation with α-bromoacetophenones, represent advanced intermediates for the synthesis of different nitrogenous heterocycles. We report their application for the synthesis of 2-aryl-3-alkylamino-1H-indoles via base-mediated C-arylation reactions followed by the reduction of the C-arylated intermediates. Linear precursors for C-arylation were prepared on solid-phase support from simple, commercially available building blocks. The effects of different substituents on the amino and aryl groups were addressed.

Solid phase synthesis of functionalized indazoles using triazenes – scope and limitations

In this study, we present a modular synthesis of highly substituted indazoles via a strategy on solid supports.

Aminofluorination of 2-alkynylanilines: a Au-catalyzed entry to fluorinated indoles

The scope and limitations of gold-catalyzed tandem cycloisomerization/fluorination reactions of unprotected 2-alkynylanilines to have access to 3,3-difluoro-2-aryl-3H-indoles and 3-fluoro-2-arylindoles are described. An unprecedented aminoauration/oxidation/fluorination cascade reaction of 2-alkynylanilines bearing a linear alkyl group on the terminal triple bond is reported.