Catalytic and Atom-Economic Intermolecular Amidoselenenylation of Alkenes

Calcium(II)-Mediated Three-Component Selenylation of gem-Difluoroalkenes: Access to α,α-Difluoroalkyl-β-selenides

A calcium-mediated three-component selenylation of gem-difluoroalkenes using alcohols as nucleophiles and N-(phenylseleno)phthalimide as the selenylation agent has been developed for the efficient synthesis of various α,α-difluoroalkyl-β-selenides. This selenylation reaction exhibits broad substrate and functional group tolerance, along with high levels of chemo- and regioselectivity. Additionally, the synthetic utility of the developed transformation in the late-stage functionalization of drug molecules was demonstrated.

Zn(OTf)2-catalyzed intra- and intermolecular selenofunctionalization of alkenes under mild conditions

Zn(OTf)2-catalyzed intra- and intermolecular selenofunctionalization of alkenes was achieved with electrophilic N-phenylselenophthalimide. This method provides straightforward and efficient access to various seleno-substituted heterocycles and vicinal Se heteroatom-disubstituted molecules under mild conditions. This reaction is compatible with various substrates/functional groups, and preliminary studies on the reaction mechanistic were also conducted.

Synthesis of β-Hydroxysulfides via Multi-Component Cascade Hydroxysulfenylation of Styrenes with NH4 SCN and Water under Transition-metal-free Conditions

Transition-mental-free multi-component hydroxysulfenylation of styrenes with NH4 SCN and water to from β-hydroxysulfides is established. The reaction mechanism proceeded via a domino reaction after a radical addition to 2-phenylimidazo[1,2-a]pyridines. This approach features a wide substrate scope and functional group compatibility, providing 34 compounds in acceptable yields.

Calcium(II)-Mediated Three-Component Selenofunctionalization of Alkenes under Mild Conditions

A mild and general protocol involving amnio- and oxyselenation of diverse alkenes for the efficient synthesis of organo-Se compounds is achieved via an environmentally benign calcium-catalyzed three-component reaction. This selenofunctionalization reaction exhibits excellent substrate/functional group tolerance and high levels of chemo- and regioselectivity. Its utility was exemplified in the late-stage functionalization and even aggregation-induced emission luminogen labeling of organo-Se compounds.

Three-Component Tandem Amidosulfenylation of Alkenes for the Synthesis of β-Succinimide Sulfides

An environmentally benign multicomponent strategy for the amidosulfenylation of alkenes for the synthesis of β-succinimide sulfides is disclosed. In this process, common disulfides smoothly act as a sulfur-based source, and N-iodosuccinimide (NIS) is used not only as a free radical initiator but also as an N-nucleophile. A broad range of functional groups are tolerated in this reaction system.

Electrochemical Radical Selenylation of Alkenes and Arenes via Se-Se Bond Activation

A novel electrochemical radical selenylation of alkenes and activated arenes without external oxidants is reported. The diselenide was fully transformed into Se-centered radicals through electrochemical Se-Se bond activation. Three-component radical carbonselenation was successfully realized using styrenes to trap the RSe radical. Besides, the direct coupling of RSe radicals with activated arenes was further developed. Using this atom-economic protocol, diversity of unsymmetric aryl-aryl, aryl-alkyl, and alkyl-alkyl selenoethers was obtained regioselectively, which has potential application in biological chemistry.

Copper-catalyzed domino synthesis of benzo[d]imidazo[5,1-b][1,3]selenazoles involving sequential intermolecular cycloaddition and intramolecular Ullmann-type C–Se bond formation

A copper-catalyzed domino synthesis of benzo[d]imidazo[5,1-b][1,3]selenazoles involving sequential intermolecular cycloaddition and intramolecular Ullmann-type C–Se bond formation has been developed.

The sunlight-promoted aerobic selective cyclization of olefinic amides and diselenides

A novel sunlight-promoted approach for the selective synthesis of selenated iminoisobenzofurans or isoindolinones via the aerobic O-cyclization or N-cyclization of olefinic amides with diselenides has been developed.

BF3·OEt2-mediated cyclization of β,γ-unsaturated oximes and hydrazones with N-(arylthio/arylseleno)succinimides: an efficient approach to synthesize isoxazoles or dihydropyrazoles

A highly efficient BF3·OEt2-mediated cyclization of β,γ-unsaturated oximes and tosylhydrazones with N-(arylthio/arylseleno)succinimides has been established for the construction of N-heterocycles in a one-step manner. This metal-free cyclization provides direct access to isoxazoles and dihydropyrazoles in good to excellent yields at room temperature. The mechanistic experiments support the formation of a cationic species PhS+ which plays a critical role in this cyclization process.

Diamine-mediated N2-selective β-selenoalkylation of triazoles with alkenes

A N2-selective β-selenoalkylation of 1,2,3-triazoles with alkenes mediated by diamines has been developed. The reaction proceeds presumably via the interaction of diamines with both the triazole moiety and selenium/alkene complex to construct a U-shaped reaction intermediate. This activation mode will block the N1 position on triazoles and thus favor the N2-selective selenoamination. This stereospecific anti-addition method enables an efficient N2-selective β-selenoalkylation of 1,2,3-triazoles under mild and open-air conditions and might find applications in the synthesis of biologically active molecules.

Recent Advances on C-Se Bond-forming Reactions at Low and Room Temperature

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Over the last decades, many methods have been reported for the synthesis of selenium- heterocyclic scaffolds because of their interesting reactivities and applications in the medicinal as well as in the material chemistry. This review describes the recent numerous useful methodologies on C-Se bond formation reactions which were basically carried out at low and room temperature.

An organoselenium-catalyzed N1- and N2-selective aza-Wacker reaction of alkenes with benzotriazoles

A novel and practical organoselenium-catalyzed, N¹- and N²-selective controllable aza-Wacker reaction is realized, which provides an easy access to N¹- and N²-olefinated benzotriazole derivatives.

Efficient Protocol for Synthesis of β-Hydroxy(alkoxy)selenides via Electrochemical Iodide-Catalyzed Oxyselenation of Styrene Derivatives with Dialkyl(aryl)diselenides

An efficient protocol for the synthesis of β-hydroxy(alkoxy)selenides was developed through the electrochemical iodide-catalyzed oxyselenation of styrene derivatives with dialkyl(aryl)diselenides under mild reaction conditions. Mechanistic studies showed that the cation I+ is involved during the whole process, and accelerates the formation of seleniranium ion via substitution and addition reaction with dialkyl(aryl)diselenides and styrene derivatives. The corresponding products are formed in good to excellent yields. This electrochemical oxyselenation provides an efficient strategy for difunctionalization of alkenes.

FeCl3-Catalyzed Regio-Divergent Carbosulfenylation of Unactivated Alkenes: Construction of a Medium-Sized Ring

A FeCl₃-catalyzed regio-divergent carbosulfenylation of unactivated alkenes with electrophilic N-sulfenophthalimides has been developed. This protocol provides a straightforward and efficient access to various medium-sized rings, especially strained 7- and 8-membered carborings with a sulfur atom attached. The endo/exo selectivity in the reaction depends on the atom number of the chain between arene and alkene. Broad substrate scope, high yields, and gram-scale synthesis exemplified the utility and practicability of this protocol. In addition, this methodology can be extended to the carboselenylation of isolated alkenes.

Iodine-mediated synthesis of 4-selanylpyrazoles

A new and simple procedure mediated by I₂ is developed for the preparation of 4-selanylpyrazoles from pyrazoles and diselenides.

Iron-Promoted Difunctionalization of Alkenes by Phenylselenylation/1,2-Aryl Migration

Iron-promoted difunctionalization of α,α-diaryl and α-aryl-α-alkyl allylic alcohols has been efficiently achieved by means of N-(phenylseleno)phthalimide (N-PSP) under mild conditions. An in situ generated phenylselenium cation (PhSe⁺) was added to the olefinic C═C bond to initiate the regioselective phenylselenylation with concomitant 1,2-aryl migration, following a migration preference contrary to the well-known radical pathway. Hydrazonation of the resultant alkene difunctionalization products, that is, α-aryl-β-phenylselenyl ketones, and subsequent copper-catalyzed dehydroselenylation efficiently afforded functionalized 2-pyrazoline derivatives.

Organoselenium-Catalyzed Regioselective C-H Pyridination of 1,3-Dienes and Alkenes

An efficient approach for organoselenium-catalyzed regioselective C-H pyridination of 1,3-dienes to form pyridinium salts has been developed. This method was also successfully applied to direct C-H pyridination of alkenes. Fluoropyridinium reagents, or initially loaded pyridine derivatives, acted as pyridine sources in the pyridination reactions. The obtained pyridinium salts could be further converted under different conditions. This work is the first example of catalytic C-2 direct C-H functionalization of 1,3-dienes and the first case of organoselenium-catalyzed C-H pyridination.

Convenient iodine-mediated aminoselenation of alkenes using benzotriazoles as nitrogen sources

Convenient iodine-mediated alkene aminoselenation using benzotriazoles as nitrogen sources.

Peroxodisulfate-mediated selenoamination of alkenes yielding amidoselenide-containing sulfamides and azoles

A novel intermolecular selenoamination of alkenes has been successfully developed and a series of structurally diverse vicinal amidoselenides were effectively obtained under mild heating.