Photoinduced Trifluoromethylselenolation of Aryl Halides with [Me4N][SeCF3]

A visible-light-induced metal-free trifluoromethylselenolation of aryl iodides and bromides with [Me4N][SeCF3] is described. The reaction was conducted at ambient temperature by successfully harnessing the light-sensitive SeCF3 reagent. Mechanistically, the EDA complexes between aryl halide and the -SeCF3 anion or the base might be formed and excited by light, which subsequently undergo intracomplex SET processes to generate aryl and •SeCF3 radicals as key intermediates, allowing a convenient and green access to various aryl trifluoromethyl selenoethers.

Palladium-catalyzed C-H trifluoromethylselenolation of arenes with [Me4N][SeCF3] and an oxidant

Trifluoromethylselenolation of arenes with [Me₄N][SeCF₃] in the presence of an oxidant through Pd-catalyzed C(sp²)-H activation under the assistance of a directing group is established for the first time. The reaction tolerates different directing groups and a variety of functional groups, enabling selective installation of a SeCF₃ moiety onto the ortho positions of arenes. Mechanistic studies revealed that the CF₃SeSeCF₃ intermediate in situ generated from oxidation of [Me₄N][SeCF₃] might be the real SeCF₃ reagent in the reaction.

Visible-light-promoted trifluoromethylselenolation of ortho-hydroxyarylenaminones

Development of an efficient process that employs easy to handle and shelf-stable reagents for the synthesis of trifluoromethylselenylated heterocyclics remains a daunting challenge in organic synthesis. Herein, we report a...

Visible-Light-Initiated Catalyst-Free Trifluoromethylselenolation of Arylsulfonium Salts with [Me4N][SeCF3]

The redox potential gap between arylsulfonium salt and [Me4N][SeCF3] has been clearly disclosed by CV measurements. Construction of carbon-selenium bond by overcoming this gap without using catalysts and additives is...

Synthesis and Biological Evaluation of CF3 Se-Substituted α-Amino Acid Derivatives

Several CF₃ Se-substituted α-amino acid derivatives, such as (R)-2-amino-3-((trifluoromethyl)selanyl)propanoates (5 a/6 a), (S)-2-amino-4-((trifluoromethyl)selanyl)butanoates (5 b/6 b), (2R,3R)-2-amino-3-((trifluoromethyl)selanyl)butanoates (5 c/6 c), (R)-2-((S)-2-amino-3-phenylpropanamido)-3-((trifluoromethyl)selanyl)propanoates (11 a/12 a), and (R)-2-(2-aminoacetamido)-3-((trifluoromethyl)selanyl)propanoates (11 b/12 b), were readily synthesized from natural amino acids and [Me₄ N][SeCF₃ ]. The primary in vitro cytotoxicity assays revealed that compounds 6 a, 11 a and 12 a were more effective cell growth inhibitors than the other tested CF₃ Se-substituted derivatives towards MCF-7, HCT116, and SK-OV-3 cells, with their IC₅₀ values being less than 10 μM for MCF-7 and HCT116 cells. This study indicated the potentials of CF₃ Se moiety as a pharmaceutically relevant group in the design and synthesis of novel biologically active molecules.

Trifluoromethylselenolation and N-acylation of indoles with [Me4N][SeCF3]

An efficient method for oxidative trifluoromethylselenolation/N-acylation of indoles with excess [Me₄N][SeCF₃] in the presence of acyl peroxides and their derivatives is described. The reaction is easy to handle, proceeds smoothly at room temperature under metal-free conditions, and shows advantages such as good functional group tolerance, excellent regioselectivity, and compatibility of a number of substrates, producing 1-acyl and 3-trifluoromethylselanyl substituted indoles in good yields. Acyl peroxides and peroxycarboxylic acid behave as both oxidants and acyl sources in the transformation. This one-pot procedure provides a convenient access to a new class of indole derivatives, representing the first trifluoromethylselanyl bifunctionalization of indoles with the nucleophilic [Me₄N][SeCF₃] reagent.

SELENIUM AS A VERSATILE REAGENT IN ORGANIC SYNTHESIS: MORE THAN ALLYLIC OXIDATION

For many years since its discovery, Selenium has played the role of a bad boy who became a hero in organic transformations. Selenium dioxide, for instance, is one of the most remembered reagents in allylic oxidations, having been applied in the synthesis of several naturally occurring products. The main goal of this review is to show the recent advances in the use of classical and new selenium reagents in organic synthesis. As demonstrated through around 60 references discussed in this study, selenium can go even forward as a versatile reagent. We bring a collection of selenium reagents and their transformations that are still hidden from most synthetic organic chemists.

Copper-Catalyzed Radical 1,2-Carbotrifluoromethylselenolation of Alkenes under Ambient Conditions

We have described a copper-catalyzed radical 1,2-carbotrifluoromethylselenolation of alkenes using the readily available alkyl halides and (Me₄N)SeCF₃ salt. Critical to the success is the use of a proline-based N,N,P-ligand to enhance the reducing capability of copper for easy conversion of diverse alkyl halides to the corresponding radicals via a single-electron transfer process. The reaction features a broad substrate scope, including various mono-, di-, and trisubstituted alkenes with many functional groups.

Facile synthesis of selenocarbamyl fluorides, selenoureas and their derivatives with [Me4N][SeCF3]

[Me4N][SeCF3] has proved to be an excellent precursor of Se=CF2 for amines in the preparation of selenocarbamoyl fluorides, selenoureas, and their derivatives under catalyst- and additive-free conditions, which are otherwise difficult to synthesize by other methods.

Markovnikov-Type Hydrotrifluoromethylchalcogenation of Unactivated Terminal Alkenes with [Me4N][XCF3] (X = S, Se) and TfOH

The first Markovnikov-type hydrotrifluoromethylselenolation of unactivated terminal alkenes with the readily accessible [Me₄N][SeCF₃] reagent and the superacid TfOH is reported. The reaction proceeded at room temperature under catalyst- and additive-free conditions to give the branched trifluoromethylselenolated products in good yields. This protocol is also applicable to the Markovnikov-type hydrotrifluoromethylthiolation of unactivated terminal alkenes using [Me₄N][SCF₃]/TfOH, but not to the hydrotrifluoromethoxylation with CsOCF₃/TfOH under the same conditions. The successful hydrotrifluoromethylselenolation and hydrotrifluoromethylthiolation showed simplicity and high regioselectivity, taming the sensitive ⁻XCF₃ (X = Se, S) anions with TfOH, and offered a convenient method for the straightforward synthesis of branched trifluoromethyl selenoethers and thioethers from unactivated alkenes.