Synthesis of α,α-Difluoromethylene Amines from Thioamides Using Silver Fluoride

We developed a mild, rapid process employing AgF and thioamides to produce α,α-difluoromethylene amines efficiently. This method exhibited remarkable tolerance toward various functional groups present in N-sulfonylthioamides, thereby broadening the scope of difluoromethylene sulfonamides through a straightforward approach. Additionally, we applied this approach to synthesize various perfluoroalkyl amines, establishing practical synthetic routes for exploring these compounds in pharmaceutical chemistry and materials science.

Recent Advances in the Synthesis of N-fluoroalkyl Amides/Sulfonamides and Their Carbonyl/Sulfonyl Derivatives

Organofluorine compounds have consistently demonstrated practical applications in the life sciences due to the fascinating properties imparted by the fluorine substituents. In recent years, significant advancements have been made in the synthesis of N-fluoroalkyl carbonyl and sulfonyl compounds. This review offers a current overview of the various synthetic routes for N-fluoroalkyl amides/sulfonamides and their transformation to new unexplored N-fluoroalkyl carbonyl/sulfonyl derivatives, categorized into three parts based on the different fluoroalkyl groups.

Access to N-Difluoromethyl Amides, (Thio)Carbamates, Ureas, and Formamides

The first efficient access to N-difluoromethyl amides, carbamates, thiocarbamates, ureas, formamides, and their derivatives is reported herein. The synthetic strategy relies on the initial synthesis and straightforward derivatization of N-CF2H carbamoyl fluorides, which were prepared through a desulfurization-fluorination of thioformamides (─NH─C(H)═S) coupled with carbonylation. The newly made N-CF2H carbonyl compounds proved to be highly robust and compatible with numerous chemical transformations and downstream derivatizations, underscoring the potential of this novel motif as a building block in complex functional molecules.

(Z)-Selective Synthesis of Bromofluoroalkenes via the TMSCF2Br-Mediated Tandem Reaction with para-Quinone Methides

We report herein a tandem reaction of para-quinone methides with TMSCF₂Br to construct bromofluoroalkenes in a Z-selective manner. While TMSCF₂Br has been documented as the precursor of difluoro carbene, it exhibits another possibility in this transformation, a formal bromofluoro carbene surrogate. The alkenyl bromide unit of the products could directly engage in a variety of transformations.

N-Difluoromethylation of N-pyridyl-substituted anilines with ethyl bromodifluoroacetate

A general protocol for N-difluoromethylation of aniline derivatives is developed. Commercially available ethyl bromodifluoroacetate serves as a difluorocarbene source in the presence of a base. This carbene surrogate is attractive owing to its favorable stability, environmental friendliness and inexpensiveness. This reaction system features notable operational simplicity (bench top-grade solvents can be used without any pre-drying and do not require inert atmosphere protection). A wide range of functional groups in aniline derivatives are well-tolerated, and good-to-excellent product yields are generally obtained.

Recent progress on selective deconstructive modes of halodifluoromethyl and trifluoromethyl-containing reagents

Halodifluoromethyl and trifluoromethyl-containing compounds are widely employed in organic chemistry, pharmaceuticals and materials science. Therefore, their applications and transformations have received significant attention during the past few decades. The single, double, triple and quadruple cleavage of halodifluoromethyl compounds and various deconstructive modes of trifluoromethyl-containing compounds could generate a variety of synthons to prepare more valuable products. Herein, we summarize the most significant achievements in this field with an intriguing focus on results from the last decade.

A simple method for the synthesis of N-difluoromethylated pyridines and 4-pyridones/quinolones by using BrCF2COOEt as the difluoromethylation reagent

We describe a novel transition metal-free method for the synthesis of N-difluoromethylated pyridines and 4-pyridones/quinolones by using readily available ethyl bromodifluoroacetate as a fluorine source. The formation of N-difluoromethylated pyridines involves a two-step process in which N-alkylation by ethyl bromodifluoroacetate is followed by in situ hydrolysis of the ester and decarboxylation. Besides optimizing the N-difluoromethylation conditions and assessing the influence of steric and electronic effects on the outcome of the reaction, we have synthesized the N-difluoromethylated analogues of two fluorophores and demonstrated that their spectroscopic properties can be improved through replacement of N-CH₃ group by N-CF₂H.

A simple transition-metal free method was developed for the synthesis of N-difluoromethylated pyridinium-containing compounds and 4-pyridones/quinolones.