Oxidative trifluoromethyl(thiol/selenol)ation of terminal alkynes: An overview

Exploring α-electron-deficiency-induced [1,2]-fluorine migration

The present study investigates the standard model of [1,2]-fluorine migration and that triggered by the rearrangement of cyclopropyl-substituted fluoroepoxides. The [1,2]-fluorine migration reaction proceeds via a synchronous concerted, tight-ion-pair mechanism. When coupled with other reaction coordinates, the whole reaction follows an asynchronous mechanism, while the [1,2]-fluorince migration unit still retains its tight-ion-pair feature and the reaction coordinates of two C-F distances vary synchronously. A general reaction program for α-electron-deficiency-induced [1,2]-fluorine migration is proposed through an analysis of the intermediates generated from nucleophilic addition. The reaction mechanisms associated with α-electron deficiency and the rearrangement are scrutinized using computational chemistry. Two additional reaction programs for [1,2]-fluorine migration are identified. The Gibbs free energy change of [1,2]-fluorine migration exhibits a linear dependence on the value of the Fukui function of the substrate, which could lead to the production of the desired α-monofluoroketone and enhance the utilization of fluorine atoms.

Lewis Acid Promoted Vicinal Oxytrifluoromethylselenolation of Alkenes

Herein, we have developed a metal-free, Lewis acid promoted vicinal oxytrifluoromethylselenolation of alkenes using trifluoromethyl selenoxides as electrophilic trifluoromethylselenolation reagents and alcohols as nucleophiles. With less steric and good nucleophilic solvents (such as ethanol and methol), Tf₂O-catalyzed oxytrifluoromethylselenolation could be realized, while stoichiometric Tf₂O was required to promote full transformation with less nucleophilic and steric solvents (such as isopropanol and tert-butanol). The reaction featured good substrate scope, functional group compatibility, and diastereoselectivity. This method could be further applied to oxytrifluoromethylselenolation, aminotrifluoromethylselenolation with stoichiometric nucleophiles under modified conditions. A mechanism involving a seleniranium ion was proposed based on the preliminary results.

Asymmetric Double Oxidative [3 + 2] Cycloaddition for the Synthesis of CF3-Containing Spiro[pyrrolidin-3,2'-oxindole]

An asymmetric double oxidative [3 + 2] cycloaddition is reported. Oxidation of 3-((2,2,2-trifluoroethyl)amino)indolin-2-ones and β-aryl-substituted aldehydes simultaneously and subsequent asymmetric cycloaddition in the presence of the chiral amino catalyst generated highly functionalized chiral CF₃-containing spiro[pyrrolidin-3,2'-oxindole] with four contiguous stereocenters stereoselectively, which is characterized by directly constructing two C-C bonds from four C(sp³)-H bonds. This new method features mild conditions, broad substrate scope, and excellent functional group compatibility.

Fe-Catalyzed Radical Trifluoromethyl-Alkenylation of Alkenes or Alkynes with 2-Amino-1,4-naphthoquinones

The first Fe-catalyzed three-component radical trifluoromethyl-alkenylation of alkenes with 2-amino-1,4-naphthoquinones and CF₃SO₂Na is reported. The developed reaction enables the highly regioselective preparation of a variety of valuable CF₃-substituted 1,4-naphthoquinones in acceptable yields. In the light of the catalytic system, alkynes smoothly afford the corresponding three- or four-component trifluoromethyl-alkenylation products. This protocol features use of easily available and inexpensive reagents, broad substrate scope, and simple reaction conditions.

Trifluoromethyl Selenoxides: Electrophilic Reagents for C-H Trifluoromethylselenolation of (Hetero)Arene

The trifluoromethylselenyl group (CF₃Se) has become an emerging fluorinated moiety in synthetic chemistry due to its high Hansch lipophilicity parameter and strong electron-withdrawing effect. The trifluoromethylselenolation is hampered by limited synthetic methods and related reagents. Herein, we designed and synthesized the new electrophilic trifluoromethylselenolation reagents, trifluoromethyl selenoxides, which are easy to prepare and easy-to-handle and are not moisture or air sensitive. The selenoxides are successfully applied to metal-free C-H trifluoromethylselenolation of a series of (hetero)arenes.

Perfluoroalkylation of Terminal Alkynes with Perfluoroalkyl Iodides Catalyzed by an Iron Salt

The one-step, direct perfluoroalkylation of terminal alkynes with perfluoroalkyl iodides has been developed in which a simple ligandless iron salt is employed as the catalyst. Various perfluoroalkylated alkynes could be afforded in good to excellent yields with good functional group compatibility. Preliminary mechanistic studies suggest the involvement of the perfluoroalkyl radical in the catalytic cycle and the perfluoroalkylated alkenyl iodides as intermediates. The method provides straight, streamlined, and sustainable access to perfluoroalkylated acetylenes.

A straightforward access to trifluoromethylated natural products through late-stage functionalization

This review summarizes the applications of late-stage strategies in the direct trifluoromethylation of natural products in the past ten years, with particular emphasis on the reaction model of each method.

Direct selenosulfonylation of unsaturated compounds: a review

In this review, we have discussed recent developments on the direct selenosulfonylation of unsaturated compounds which lead to the formation of two new carbon-sulfur and carbon-selenium bonds in a single operation. The reactions were classified based on the type of starting unsaturated compound and product. Thus, the review is divided into three major sections. The first describes the current literature on selenosulfonylation of alkenes. The second section covers the available literature on selenosulfonylation of alkynes. The third focuses exclusively on selenosulfonylation of allenes.

In this review, we have discussed recent developments on the direct selenosulfonylation of unsaturated compounds which lead to the formation of two new carbon-sulfur and carbon-selenium bonds in a single operation.

Direct halosulfonylation of alkynes: an overview

The difunctionalization reactions of easily available and inexpensive alkynes have emerged as a reliable, powerful, and step-economical approach for the construction of highly substituted complex alkenes in a one-pot manner, without the need for isolation of intermediates. A wide variety of transformations based on this concept have been successfully achieved for the preparation of synthetically and biologically important β-halovinyl sulfone scaffolds. In this Review, we summarize the recent advances and developments in this field and present a comprehensive overview of halosulfonylation of alkyne substrates with emphasis on the mechanistic features of the reactions.

Amphetamine Drug Detection with Inorganic MgO Nanotube Based on the DFT Calculations

In this study, the main challenge was to focus on the detection of amphetamine (AN) using a type of magnesium oxide nanotube (MgONT) sensor through density functional theory (DFT) calculations. Nowadays, due to the adverse effects of drug abuse, governments put all their efforts into detecting and managing illegal drugs such as AN. Therefore, the detection of AN in biological specimens is of great importance. In this study, through DFT calculations, the intrinsic sensing properties of MgONT were investigated for the detection of AN. We concluded that the MgONT considerably enhances the reactivity of the MgONT toward AN. Furthermore, the sensing response for the MgONT was 392.36. The results showed that there was a considerable change in the energy levels of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) and there was a drop in the band gap value (E_g). This decrease in the E_g value improved the electrical conductivity. Moreover, desorption of AN from the surface of the MgONT had a slight recovery time (~ 22.89 ms). This work illustrated that MgONT could be considered a proper candidate for electronic sensing and AN drug delivery in biological systems.

The adsorption of cathinone drug on the platinum decorated silicon carbide nanosheets: DFT studies

Cathinone (CTN), classified as stimulants, is one of the psychoactive drugs. Although the sale of CTN was controlled by international drug laws, it was still sold on the internet, and its overdose caused many deaths worldwide. As chemical sensors, two-dimensional (2D) nanomaterials have drawn attention to be used in various biological molecules. In the current study, the sensing characteristics of the intrinsic SiC monolayer (SiCM) and its Pt-decorated state (Pt@SiCM) were scrutinized toward the CTN drug by utilizing density functional theory (DFT) calculations. It was illustrated that the SiCM sensing response to CTN is insignificant (~ 10.6 at 298 K) due to the weak interaction with the adsorption energy of -0.25 eV. After the decoration of Pt on the SiCM, it was adsorbed above a hexagonal ring, which formed an η⁶-Pt half-sandwich and the adsorption energy was -3.62 eV. It was found that the Pt@SiCM strongly adsorbed CTN and the adsorption energy was -1.60 eV. Therefore, Pt-decoration augmented the SiCM sensing response to CTN from 10.3 to 716.6. The recovery time obtained for the CTN desorption from the Pt@SiCM surface was 12.7 s, which was short. It was concluded that Pt-decoration makes the SiCM a favorable candidate for CTN identification.

Recent advances in intermolecular 1,2-difunctionalization of alkenes involving trifluoromethylthiolation

Trifluoromethylthiolative difunctionalization of alkenes, a cheap and abundant feedstock, which installs a trifluoromethylthiol (SCF₃) group and another unique functional group across the carbon–carbon double bonds, provides an ideal strategy for the preparation of β-functionalized alkyl trifluoromethyl sulfides and has become a hot topic recently.