Synthesis of CuI Trifluoromethylselenates for Trifluoromethylselenolation of Aryl and Alkyl Halides

The development of new strategies for synthesis of trifluoromethylthiolate compounds is of considerable importance in pharmaceuticals, agrochemicals, and advanced materials. Accordingly, currently much attention is being devoted to the development of effective methods and reagents for their synthesis. In contrast, considerably less effort has been afforded to the development of preparing C?SeCF₃ bonds. Herein we report a concise route to synthesize a family of copper(I) trifluoromethylselenolate reagents by the reaction of CuI with the Ruppert’s reagent (Me₃SiCF₃), KF, and elemental selenium in the presence of dinitrogen ligands in CH₃CN at room temperature. The reagent [Cu(bpy)(SeCF₃)]₂ was proven to be air‐stable and highly efficient for nucleophilic trifluoromethylthselenolation of a broad range of (hetero)aryl halides and alkyl halides. This method represents a powerful protocol for the construction trifluoromethylselenolate compounds.     

Visible‐Light‐Mediated Metal‐Free Synthesis of Trifluoromethylselenolated Arenes

The first visible‐light‐mediated synthesis of trifluoromethylselenolated arenes under metal‐free conditions is reported. The use of an organic photocatalyst enables the trifluoromethylselenolation of arene diazonium salts using the shelf‐stable reagent trifluoromethyl tolueneselenosulfonate at room temperature. The reaction does not require the presence of any additives and shows high functional‐group tolerance, covering a very broad range of starting materials. Mechanistic investigations, including EPR spectroscopy, luminescence investigations, and cyclic voltammetry allow rationalization of the reaction mechanism.     

Nickel-Catalyzed Electrochemical Synthesis of (Hetero)Aryl Trifluoromethyl Selenides

A convenient and efficient approach for the construction of aryl trifluoromethyl selenoethers from aryl iodides under mild conditions is reported. Electrochemical activation of stable and inexpensive NiBr₂bipy (bipy – bipyridine) complex instead of labile Ni(COD)₂ (COD – cyclooctadiene) catalyst. [NMe₄][SeCF₃] is employed as shelf-stable source of SeCF₃ fragment. The reaction tolerates a wide range of substrates, including modification of drug-like molecules. Cyclic voltammetry studies allow insight into the reaction mechanism.     

Fluoroalkylation of Diazo Compounds with Diverse Rfn Reagents

Progress in the transition‐metal‐catalyzed or ‐free fluoroalkylation of diazo compounds with different types of fluoroalkyl (R_fn) transfer reagents is summarized in this review. Special attention is focused on the straightforward trifluoromethylation, gem‐difluoroolefination, trifluoromethoxylation, fluoroalkylthiolation, and trifluoromethylselenolation of diazo substrates. The mechanistic insights and the application of some of the products are also discussed in this article. We believe that this review will inspire both young and experienced chemists to further study the direct fluoroalkylation of diazo compounds as an efficient and convenient way to build complex fluorine‐containing molecules.     

Direct Trifluoromethylselenolation and Fluoroalkylselenolation of C−H Bonds: Recent Advances in Reagents Development and Reactions

Due to their high lipophilicity and strong electron-withdrawing property, more and more attention has been paid to introducing trifluoromethylseleno and fluoroalkylseleno moieties into organic molecules. In this short review, we categorize the synthesis of compounds that combine selenium and fluorinated moieties into two main types: trifluoromethylselenolation (CF₃Se) and fluoroalkylselenolation (R_fSe, except CF₃Se). This review aims to provide a summary of the recent advances in direct C−H trifluoromethylselenolation and fluoroalkylselenolation from the synthesis of trifluoromethylselenolation and fluoroalkylselenolation reagents to their application. Based on the method of how the R_fSe group was introduced, the main content is divided into three parts: transition-metal-free reactions, transition-metal-mediated/catalyzed reactions and photo-catalyzed reactions. The general substrate scope, mechanism and limitations would also be discussed so that we hope the review will serve as an inspiration for further research in this appealing research field.     

Vinylic Trifluoromethylselenolation via Pd-Catalyzed C−H Activation

Trifluorometylselenolation via C−H activation is barely described in literature. In particular, no such vinylic functionalization has been yet described. Herein, a palladium-catalyzed trifluoromethylselenolation of vinylic C−H bonds is described. The 5-methoxy-8-aminoquinoline has been used as auxiliary directing group to perform this reaction. The reaction gives excellent yields with α-substituted compounds whatever the substituents and a microwave activation can be used to accelerate the reaction. With β-substituted substrates lower yields, but still satisfactory, are obtained. This methodology was also successfully extended to other fluoroalkylselenyl groups.     

Aromatic Trifluoromethylselenolation via Pd-catalyzed C−H functionalization

The synthesis of trifluoromethylselenolated aromatic molecules via an auxiliary-assisted, palladium catalyzed, C−H bonds functionalization with trifluoromethyl tolueneselenosulfonate as reagent is described. The mono- or bis-products can be preferentially formed. Some mechanistic investigations were realized to better understand the reaction. This methodology was also extended to fluoroalkylselenyl groups.