Electrophilic Reagents for the Direct Incorporation of Uncommon SCF2CF2H and SCF2CF3 Motifs

Organocatalytic enantioselective α-difluoromethylketone thiolation of β-keto esters using phthalimide-SCF2COAr

The first asymmetric α-difluoromethylketone thiolation of diverse β-keto esters using an electrophilic phthalimide-SCF2COAr reagent (PhthN-SCF2COAr) was reported. In the presence of cinchona-alkaloid-based catalyst (DHQD)2PHAL, the reaction was achieved in moderate yields with a moderate to excellent enantioselectivity (up to 93% ee) under mild reaction conditions and exhibited functional group compatibility. An ammonium hydrogen-bonded induction model was proposed to rationalize the origin of enantioselectivity.

Nitrogen-Based Organofluorine Functional Molecules: Synthesis and Applications

Fluorine and nitrogen form a successful partnership in organic synthesis, medicinal chemistry, and material sciences. Although fluorine-nitrogen chemistry has a long and rich history, this field has received increasing interest and made remarkable progress over the past two decades, driven by recent advancements in transition metal and organocatalysis and photochemistry. This review, emphasizing contributions from 2015 to 2023, aims to update the state of the art of the synthesis and applications of nitrogen-based organofluorine functional molecules in organic synthesis and medicinal chemistry. In dedicated sections, we first focus on fluorine-containing reagents organized according to the type of fluorine-containing groups attached to nitrogen, including N-F, N-RF, N-SRF, and N-ORF. This review also covers nitrogen-linked fluorine-containing building blocks, catalysts, pharmaceuticals, and agrochemicals, underlining these components' broad applicability and growing importance in modern chemistry.

Electrophilic glycoluril-based reagents for atom-economic thiocyanation and selenocyanation of (hetero)arenes

Two electrophilic glycoluril-based N-XCN reagents (X = S, Se) were developed for introducing SCN/SeCN groups into aromatic substrates, including the late-stage modification of bioactive molecules. Their application produces minimal waste, enables simple purification, and offers potential for reagent regeneration. Additionally, their compatibility with green solvents and flow technology was demonstrated. The sustainability of the process was evaluated using green metrics and Ecoscale values, emphasizing the complementary roles of the reagents and solvent recovery in enhancing atom economy and reducing waste.

Impact of Fluorine Pattern on Lipophilicity and Acid-Base Properties of 2-(Thiofluoroalkyl)pyridines: Insights from Experiments and Statistical Modeling

Lipophilicity and acid-base properties are two key aspects of the optimization of a compound in drug discovery. Using 19F NMR, we experimentally determined the log D7.4 of a wide array of 2-thiofluoroalkyl (SRF) and 2-sulfonyl fluoroalkyl (SO2RF) substituted pyridines and the pKa values of their protonated counterparts. Statistical modeling based on constitutional and DFT descriptors provided further insights into the structure-property relationship, explaining the experimental observations and predicting log D7.4 values. Our results highlight the influence of fluorination topology in SRF fragments and demonstrate the dual effect of fluorine on molecular polarity, increasing the hydrophobic surface and the polarity of the sulfur moiety. By analyzing methyl- and ethyl-derived fragments, we found a gradient in log D7.4 values influenced by the oxidation state of the sulfur atom and fluorination pattern. Our findings emphasize the context-dependent impact of fluorination and offer insights to better understand the impact of thiofluoroalkyl chains on these physicochemical properties.

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.

ortho-Cyanomethylation of aryl fluoroalkyl sulfoxides via a sulfonium-Claisen rearrangement

We hereby report the ortho-cyanomethylation of aryl fluoroalkyl sulfoxides with acetonitrile through a sulfonium-Claisen-type rearrangement. This reaction enables the incorporation of two valuable functional groups, such as the cyanomethyl group and the fluoroalkylthio group, into arenes. Remarkably, fluoroalkylthio groups, such as SCFH2 and SCF2H, bearing active hydrogen, are well tolerated by the reaction. The success of the reaction relies on the use of an excess amount of acetonitrile and the electronegative effect of fluoroalkyl substituents, both of which promote the electrophilic assembly of sulfoxides with acetonitrile. Consequently, the sulfonium-Claisen rearrangement reaction tolerates a wide variety of fluoroalkyl sulfoxides bearing functional groups including halides, nitriles, ketones, sulfones, and amides, which are appealing for subsequent elaboration and exploration.