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.

N-Sulfenylsuccinimide/phthalimide: an alternative sulfenylating reagent in organic transformations

In the field of organosulfur chemistry, sulfenylating agents are an important key in C-S bond formation strategies. Among various organosulfur precursors, N-sulfenylsuccinimide/phthalimide derivatives have shown highly electrophilic reactivity for the asymmetric synthesis of many organic compounds. Hence, in this review article, we focus on the application of these alternative sulfenylating reagents in organic transformations.

Lewis Acid-Mediated Electrophilic Thiolative Difunctionalization of Enimides: Rapid Access to β-Amino Sulfides

An efficient and practical route for the synthesis of β-amino sulfides by Lewis acid-mediated electrophilic thiolative difunctionalization of enimides is disclosed. A series of free phenols, electron-rich arene, alcohol, azide, and hydride, are successfully incorporated into the substrates in high regio- and stereoselectivities under mild conditions. The obtained products possess multiple functional groups and can be easily transformed to other valuable molecules.

Heterocyclization of Bis(2-chloroprop-2-en-1-yl)sulfide in Hydrazine Hydrate–KOH: Synthesis of Thiophene and Pyrrole Derivatives

The article is devoted to heterocyclization of bis(2-chloroprop-2-en-1-yl)sulfide which proceeds in hydrazine hydrate–alkali medium and leads to formation of thiophene and pyrrole derivatives: previously described 4,5,9,10-tetrahydrocycloocta[1,2-c;5,8-c’]dithiophene, as well as unknown hydrazone of 5-methylidene-3-methyldihydrothiophen-2-one and 1-amino-2-(propynylsulfanylpropenylsulfanyl)-3,5-dimethylpyrrole. Tentative mechanisms for the formation of the heterocyclic products are discussed. Obtained hydrazone of 5-methylidene-3-methyldihydrothiophen-2-one was used for the synthesis of a range of azine derivatives and in oxidation process with SeO₂. The found reactions open up expedient approaches to the formation of various hardly accessible thiophene and pyrrole compounds from 2,3-dichloropropene and elemental sulfur as starting reagents.

Facile preparation of dihydro-1,4-benzothiazine derivatives via oxidative ring-expansion of 2-aminobenzothiazoles with olefins

A concise and efficient approach to prepare dihydro-1,4-benzothiazine derivatives is described via oxidative ring-expansion of 2-aminobenzothiazoles with olefins under metal-free conditions. This protocol is applicable for a wide range of readily accessible 2-aminobenzothiazoles and olefins with moderate-to-good yields. The [4+2] heteroannulation between the intermediacy of oxidative ring-opening of 2-aminobenzothiazoles and olefins is suggested to rationalize the formation of the product.

Recent advances in thiolation via sulfur electrophiles

This review systematically summarizes the recent developments for constructing sulfur compounds from sulfur electrophiles, and the mechanism mainly involved thirranium ions, sulfur ylides, C–S cross coupling and electrophilic substitution.

An aryl thiol-vinyl azide coupling reaction and a thiol-vinyl azide coupling/cyclization cascade: efficient synthesis of β-ketosulfides and arene-fused 5-methylene-2-pyrrolidinone derivatives

The addition reaction of thiol to vinyl azide has been extensively studied. Variously substituted aryl thiols are all viable for this coupling process. The scope of the other partner is successfully expanded from α-aryl vinyl azide to α-alkyl vinyl azide. A thiol-vinyl azide coupling/cyclization cascade is realized with substituted aryl vinyl azides carrying a 2-methoxycarbonyl group. The value of β-ketosulfide products was demonstrated by its application in S-heterocycle synthesis.

Synthetic developments on the preparation of sulfides from thiol-free reagents

This critical review covers the main thiolating reagents with respect to their characteristics and reactivities. In fact, they are complementary to each other and bring different thiolation strategies, avoiding the hazardous thiol derivatives.

Metal-free efficient thiolation of C(sp2) functionalization via in situ-generated NHTS for the synthesis of novel sulfenylated 2-aminothiazole and imidazothiazole

A direct metal-free approach for the synthesis of novel sulfenylated 2-aminothiazole and imidazothiazole derivatives at room temperature is reported via an in situ-generated electrophilic thiolating agent.

Synthesis of 4-chalcogenyl pyrazoles via electrophilic chalcogenation/cyclization of α,β-alkynic hydrazones

A facile method for the synthesis of 4-chalcogenylated pyrazoles has been developed via electrophilic chalcogenation/cyclization of α,β-alkynic hydrazones. The cyclization of α,β-alkynic aldehyde hydrazones could be induced by using either sulfenyl chloride or the S-electrophiles generated in situ from the reaction of NCS and arythiol. The developed method was successfully applied to the synthesis of the sulfenyl analogue of celecoxib.

Copper-Catalyzed Regioselective Aminothiolation of Aromatic and Aliphatic Alkenes with N-Fluorobenzenesulfonimide and Thiols through Three-Component Radical Coupling

Copper-catalyzed regioselective aminothiolation of terminal and internal alkenes with N-fluorobenzenesulfonimide and thiols has been developed. The three-component reaction is promoted by the addition of dimethyl sulfide. In addition to aromatic alkenes, aliphatic alkenes are subjected to the reaction, affording various aminothiolation adducts as single regioisomers. The radical process is proposed by preliminary mechanistic studies, involving radical trap and radical clock experiments.

A facile and regioselective multicomponent synthesis of chiral aryl-1,2-mercaptoamines in water followed by monoamine oxidase (MAO-N) enzymatic resolution

A facile microwave assisted three-component protocol allows the synthesis of chiral aryl-1,2-mercaptoamines in water in a few minutes with high yields, bypassing the use of toxic aziridine intermediates. The chiral 1,2-mercaptoamines were then deracemized through enzymatic resolution of the racemates using monoamine oxidase (MAO-N) biocatalysts.

N-Alkynylthio Phthalimide: A Shelf-Stable Alkynylthio Transfer Reagent for the Synthesis of Alkynyl Thioethers

A new kind of electrophilic alkynylthiolating reagent, called N-alkynylthio phthalimide, is designed and synthesized herein. This electrophilic sulfenylating reagent can be easily prepared in three steps from commercially available phthalimide and corresponding silver acetylide. Furthermore, the N-alkynylthio phthalimides are demonstrated to be efficient alkynylthio transfer reagents that can react with various C-nucleophiles, including β-ketoesters, aryl boronic acids, and Grignard reagents to afford a diverse range of alkynyl thioethers under mild conditions.

Catalytic Regio- and Stereoselective Alkene Sulfenoamination for 1,4-Benzothiazine Synthesis

An alkene sulfenoamination reaction with 2-aminothiophenol is developed using iodide catalysis. This reaction renders access to useful 1,4-benzothiazines with good functional group compatibility including both electron-donating and electron-withdrawing substituents. The reaction is proposed to proceed through an inversion of the polarity of the thiol functionality. Our mechanistic studies reveal that both thiiranium and thiyl radical pathways are plausible and that the disulfide reagent can also function as a viable substrate in this reaction.