Direct Dehydrogenative Access to Unsymmetrical Phenones

A unified flow strategy for the preparation and use of trifluoromethyl-heteroatom anions

The trifluoromethyl group (CF3) is a key functionality in pharmaceutical and agrochemical development, greatly enhancing the efficacy and properties of resulting compounds. However, attaching the CF3 group to heteroatoms such as sulfur, oxygen, and nitrogen poses challenges because of the lack of general synthetic methods and reliance on bespoke reagents. Here, we present a modular flow platform that streamlines the synthesis of heteroatom-CF3 motifs. Our method uses readily available organic precursors in combination with cesium fluoride as the primary fluorine source, facilitating the rapid generation of N-trifluoromethyl(R) [NCF3(R)], SCF3 (trifluoromethylthio), and OCF3 (trifluoromethoxy) anions on demand without reliance on perfluoroalkyl precursor reagents. This strategy offers a more environmentally friendly synthesis of trifluoromethyl(heteroatom)-containing molecules, with the potential for scalability in manufacturing processes facilitated by flow technology.

Deselenylative Acylation and Nitration of Monoselenides

A deselenylative protocol that enables the construction of the C-C and C-N bonds has been disclosed. By using acyl chloride/AgOTf as an efficient acylation reagent, diarylselenides smoothly undergo deselenylative acylation to produce a series of aroyl compounds. In addition, deselenylative nitration can be enabled by a mild nitration reagent consisting of TsCl and AgNO3, furnishing a diverse array of nitroaromatic compounds.

Facile Friedel-Crafts alkylation of arenes under solvent-free conditions

The Friedel-Crafts alkylation of arenes is an important part of electrophilic aromatic substitution reactions. However, the reactivity of arenes is weakened by electron-withdrawing substituents, leading to limited substrate scopes and applications. Herein, we developed an efficient HOTf-promoted Friedel-Crafts alkylation reaction of broad arenes with α-aryl-α-diazoesters under metal-free and solvent-free conditions.

Meerwein Arylation of Aryl(alkyl)idenemalononitriles and Diazonium Salts for the Synthesis of 2-(Aryl(alkyl)/arylmethylene)malononitrile Derivatives

A metal-free Meerwein arylation reaction from aryl(alkyl)idenemalononitriles and diazonium salts for the synthesis of 2-(aryl(alkyl)/arylmethylene)malononitrile derivatives under mild conditions was well developed. Different from the general addition reactions between alkenes and diazonium salts, this study performed the traditional coupling reaction for the formation of C(sp2)-C(sp2) bond arylation products. The radical reaction mechanism was well verified in the control experiments. The other advantages of the approach are broad-scope substrates and good group tolerance. Moreover, the obtained products can be readily converted into high-value asymmetric ketones and hydrogenation reactions.

Selectfluor-Promoted Reactions of Aryl Methyl Ketones with Dimethyl Sulfoxide to Give 2,5-Diacylthiophenes and β-Acyl Allylic Methylsulfones

In this paper, a convenient synthesis of 2,5-diacylthiophenes and β-acyl allylic methylsulfones from aryl methyl ketones with dimethyl sulfoxide (DMSO) through Selectfluor-promoted cascade cyclization and cross-coupling reactions by simple solvent modification is described. This method enables the formation of new C-C and C-S bonds via the selection of different solvent ratios, in which DMSO molecules as synthons can be selectively introduced into methyl ketones. The features of this transformation include readily available starting materials, excellent chemoselectivity, and good functional group tolerance.