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The Friedel–Crafts arylation is among the most known organic reactions, usually being promoted by a Lewis acid, that have been employed for the synthesis of bis-indolyl methanes. Herein, we report a mild, inexpensive, green and organocatalytic protocol for the promotion of a Friedel–Crafts-type reaction between indoles and aldehydes, where N-heterocyclic iod(az)olium salts are utilized as halogen-bonding catalysts, leading to the double addition of the indole motif. A variety of aliphatic and aromatic aldehydes were converted into diarylmethanes in good to high yields, while the scope of indoles was also investigated. Water was employed as the solvent, while the reaction time was short. The reaction mechanism was also studied. [ABSTRACT FROM AUTHOR]

A systematic investigation of ethynyl N‐heterocycle‐substituted‐λ3‐iodanes (ENHIs) is presented. In a straightforward one‐pot synthesis these novel reagents can be obtained in high yields bearing a variety of N‐heterocycles. Their reactivity as electrophilic alkyne group transfer reagents was benchmarked in well‐established and novel inter‐ and intramolecular group transfer reactions. [ABSTRACT FROM AUTHOR]

We present N -heterocycle-stabilized iodanes (NHIs) as suitable reagents for the mild oxidation of activated alcohols. Two different protocols, both involving activation by chloride additives, were used to synthesize benzylic ketones and aldehydes without overoxidation in up to 97% yield. Based on MS experiments an activated hydroxy(chloro)iodane is proposed as the reactive intermediate., (Copyright © 2024, Kuczmera et al.)

This article describes the application of N-heterocyclic iod(az)olium salts (NHISs) as highly reactive organocatalysts. A variety of mono- and dicationic NHISs are described and utilized as potent XB-donors in halogen-bond catalysis. They were benchmarked in seven diverse test reactions in which the activation of carbon- and metal-chloride bonds as well as carbonyl and nitro groups was achieved. N-methylated dicationic NHISs rendered the highest reactivity in all investigated catalytic applications with reactivities even higher than all previously described monodentate XB-donors based on iodine(I) and (III) and the strong Lewis acid BF 3 ., (© 2021 The Authors. Chemistry - A European Journal published by Wiley-VCH GmbH.)