A Systematic Study on the Redox Potentials of Phenazine-Derivatives in Aqueous Media: A Combined Computational and Experimental Work.

Phenazines are an emerging class of organic compounds that have been recently utilized in aqueous redox flow batteries, a promising technology for large-scale energy storage. A virtual screening based on density functional theory calculations is used to investigate the redox potentials of around 100 phenazine derivatives in aqueous media containing various electron-donating or electron-withdrawing groups at different positions. The calculations identify the crucial positions that should be functionalized with multiple hydroxy groups to design new anolytes.

From Propargylic Alcohols to Substituted Thiochromenes: -Disubstituent Effect in Intramolecular Alkyne Iodo/hydroarylation.

This work describes the 6-- cyclization of -aryl propargyl sulfides to afford 2-thiochromenes. The substitution at the propargylic position plays a crucial role in allowing intramolecular silver-catalyzed alkyne hydroarylation and -iodosuccinimide-promoted iodoarylation. Additionally, a PTSA-catalyzed thiolation reaction of propargylic alcohols was developed to synthesize the required tertiary -aryl propargyl ethers.

Gold-Catalyzed Synthesis of 1-(Indol-3-yl)carbazoles: Selective 1,2-Alkyl vs 1,2-Vinyl Migration.

Gold(III)-catalyzed cycloisomerization of α-bis(indol-3-yl)methyl alkynols selectively affords 1-(indol-3-yl)carbazoles, in a transformation that takes place through a selective 1,2-alkyl vs 1,2-vinyl migration step in the vinyl-gold intermediate generated from the initial 5-endo-spirocyclization. The reaction proceeds well with either tertiary or secondary starting alkynols as well as with a wide variety of alkyne substituents. The key role of the other indol-3-yl substituent for the unexpected selectivity in the 1,2 rearrangement has also been supported by DFT calculations that reveal a low barrier, two-step mechanism in the alkyl migration path where the second indole significantly stabilizes a carbocationic intermediate.

Synthesis of α-functionalized α-indol-3-yl carbonyls through direct S reactions of indol-3-yl α-acyloins.

A new and efficient synthesis of α-functionalized α-indol-3-yl ketones from easily available indolyl α-acyloins is reported. This process, catalyzed by Brønsted or Lewis acids, involves an uncommon direct nucleophilic substitution reaction of a secondary α-carbonyl-substituted hydroxyl group. The described methodology allows the introduction of a variety of nucleophiles such as (hetero)arenes, thiophenols, nitroanilines and 1,3-dicarbonyl derivatives.

Synthesis of Fused Polycyclic Indoles by Brønsted Acid-Catalyzed Intramolecular Alkylation of Indoles with Alcohols.

An efficient methodology for the synthesis of a series of new fused polyclyclic indoles has been developed by Brønsted acid-catalyzed intramolecular Friedel-Crafts reactions of properly designed indolyl alcohols.