2,2-Difluoroethylation of Heteroatom Nucleophiles via a Hypervalent Iodine Strategy

The 2,2-difluoroethyl group is an important lipophilic hydrogen bond donor in medicinal chemistry, but its incorporation into small molecules is often challenging. Herein, we demonstrate electrophilic 2,2-difluoroethylation of thiol, amine and alcohol nucleophiles with a hypervalent iodine reagent, (2,2-difluoro-ethyl)(aryl)iodonium triflate, via a proposed ligand coupling mechanism. This transformation offers a complementary strategy to existing 2,2-difluoroethylation methods and allows access to a wide range of 2,2-difluoroethylated nucleophiles, including the drugs Captopril, Normorphine and Mefloquine.

Tandem reduction and trifluoroethylation of quinolines and quinoxalines with trifluoroacetic acid and trimethylamine borane

A metal-free tandem reduction and N-trifluoroethylation of quinolines and quinoxalines has been developed. It provided a convenient route to access trifluoroethylated tetrahydroquinolines and tetrahydroquinoxalines. This one-pot method avoids the purification process of the intermediate. Mechanistically, the in situ-generated boryl acetal species reacted with tetrahydroquinolines to generate iminiums followed by reduction to give the target compounds.

Photoredox catalyzed C-H trifluoroethylamination of heteroarenes

The first C-H trifluoroethylamination of heteroarenes with previously unknown N-trifluoroethyl hydroxylamine reagents was achieved under photoredox catalyzed conditions. In the presence of an iridium(III) photoredox catalyst, a variety of heteroarenes, such as indoles, benzofurans, and benzothiophenes, were smoothly converted to the trifluoroethylaminated products in moderate to high yields and with excellent regioselectivity.

Iron porphyrin-catalyzed N-trifluoroethylation of anilines with 2,2,2-trifluoroethylamine hydrochloride in aqueous solution

An iron porphyrin-catalyzed N-trifluoroethylation of anilines has been developed with 2,2,2-trifluoroethylamine hydrochloride as the fluorine source. This one-pot N-H insertion reaction is conducted via cascade diazotization/N-trifluoroethylation reactions. The developed transformation can afford a wide range of N-trifluoroethylated anilines in good yields using readily available primary amines and secondary anilines as starting materials.

Cyanuric Chloride-Based Reactive Dyes for Use in the Antimicrobial Treatments of Polymeric Materials

This study reports a simple and practical method to introduce antimicrobial and biofilm-controlling functions into hydroxyl- or amino-containing polymers such as cellulose using compounds derived from widely used reactive dyes. Two dichloro-s-triazine-based dyes, reactive blue 4 and sodium 4-(4,6-dichloro-1,3,5-triazinylamino)-benzenesulfonate (a colorless reactive "dye"), were covalently attached to cellulose at room temperature by replacing one chloride on the dyes with the hydroxyl groups on cellulose followed by hydrolysis under alkaline conditions to transform the remaining chloride into hydroxyl groups. The chemical reactions were confirmed by FT-IR studies, energy-dispersive X-ray spectroscopy, water contact angle measurement, and zeta potential analysis. The resulting cellulose provided powerful antimicrobial activities against Staphylococcus epidermidis (S. epidermidis, ATCC 35984, Gram-positive bacteria), Escherichia coli (E. coli, ATCC 15597, Gram-negative bacteria), and Candida albicans (C. albicans, ATCC 10231, yeast) and effectively prevented the formation of bacterial or fungal biofilms. The minimum inhibition concentrations of the hydrolyzed dyes were similar to that of phenol. In the zone of inhibition studies using phenolic compounds as positive controls, the hydrolyzed dyes and their model compound cyanuric acid demonstrated antimicrobial functions, suggesting that the antimicrobial activities were associated with the phenol-like hydroxyl groups on the triazine rings. Antimicrobial mechanism investigation indicated that the phenol-like structures on the dyed cellulose caused microbial lysis and leakage of intracellular components. The antimicrobial functions were durable upon repeated washing, and the dyed cellulose showed outstanding biocompatibility toward mammalian cells.

Alcohols as Fluoroalkyl Synthons: Ni-catalyzed Dehydrogenative Approach to Access Polyfluoroalkyl Bis-indoles

An acceptorless dehydrogenative strategy for the synthesis of polyfluoroalkylated bis-indoles is described by employing an earth-abundant nickel-based catalytic system under air. The notable feature of the present transformation is the use of bench stable and easily affordable polyfluorinated alcohols without any pre-functionalization for the introduction of precious polyfluoroalkyl groups. The developed straightforward protocol accomplished biologically relevant fluoroalkyl bis-indoles in a sustainable fashion. Extensive DFT study predicts the unique role of indole molecules which stabilizes the transition states during the dehydrogenation process of polyfluorinated alcohols, presumably through non-covalent π⋅⋅⋅π and H-bonding interactions.

Cu-Catalyzed/mediated synthesis of N-fluoroalkylanilines from arylboronic acids: fluorine effect on the reactivity of fluoroalkylamines

A copper catalyzed/mediated oxidative coupling of arylboronic acids and fluoroalkylated amines with an interesting reactivity trend is disclosed.