Chemo- and regio-selective amidation of indoles with isocyanates using borane Lewis acids

A metal-free synthetic route using boranes has been developed for the amidation of indoles. A detailed mechanistic study was carried out to understand the reaction mechanism.

Recent advances in the synthesis of indoles from alkynes and nitrogen sources

This review highlights ten years of success in the synthesis of indoles using alkynes and nitrogen sources as substrates.

Experimental results and computational insight into sequential reactions of β-(2-aminophenyl)-α,β-ynones with aryl isocyanates/benzoyl isothiocyanate

The selective formation of quinazoline vs. benzoxazine  and benzothiazine derivatives from β-(2-aminophenyl)-α,β-ynones and aryl isocyanates/benzoyl isothiocyanate was explored. DFT calculations provide a plausible rationale.

Synthesis of functional heterocycles via tandem reaction

Tandem reactions for efficient construction of nitrogen-containing heterocycles were developed. One-pot platinum(II)-catalyzed synthesis of indoles and isoquinolines has been achieved via isocyanates, which were derived from a Hofmann-type rearrangement of 2-alkynylbenzamides and 2-alkynylbenzylamides using a hypervalent iodine reagent. As an extension of this approach, trans-2,3-dihydro-4-quinolones were synthesized via acid-catalyzed intermolecular [2+2]-cycloaddition of aldehydes and carbamates, which were formed from nucleophilic addition of alcohols to isocyanate intermediates. Direct, efficient syntheses of the benzimidazo[2,1-a]isoquinoline ring system have been achieved with 2-bromoarylaldehydes, terminal alkynes, and 1,2-phenylenediamines by a microwave-accelerated tandem process in which a Sonogashira coupling, 5-endo cyclization, oxidative aromatization, and 6-endo cyclization can be performed in a single synthetic operation.