Synthesis of (Z)-Enediynes via Stereoinvertive Nucleophilic Substitution of (E)-Sulfonylethenes with Arylethynide, and Their Aggregation-Induced Optical Properties

(Z)-Enediynes were successfully synthesized from a trio of terminal ethynes through consecutive three-step reactions: iodosulfonylation of ethyne with I2/PhSO2Na, followed by ethynylations of iodo and sulfonyl moieties of the resulting iodosulfonylethene via Sonogashira-Hagihara coupling and nucleophilic addition-elimination, respectively. The molecular structure of the obtained (Z)-enediyne was fully characterized by X-ray crystal structure analysis, revealing that the nucleophilic substitution of (E)-sulfonylethene with arylethynide underwent a selective stereoinversion. The (Z)-enediynes exhibited photoluminescence in both the solution and solid states (crystals and powders). Ph2N-substituted derivatives showed remarkable solvatofluorochromism, and upon replacing the solvent from toluene to acetonitrile, the emission color changed from blue to yellow.

Reactions of alkynes with C-S bond formation: recent developments

Alkynes are important in organic synthesis. This review mainly focuses on recent advances (2013-2023) on alkynes with C-S bond formation, based on more than 30 types of sulfur reagents. The reactions of alkynes with various sulfur-containing compounds including RSSR (disulfides), RSH (thiols), S8 (elemental sulphur), alkynyl thioethers, RSCN, AgSCF3, K2S, Na2S, dithiane, RSCl, NFSI, RNCS, EtOCS2K, thiocarbamate, RSONH2, thiourea, sulfoxide, RSO2N3, CS2, RSO2NH2, RSO2NHNH2, RSO2Cl, RSO2Oar, RSO2SR', DABCO·(SO2)2, Na2S2O5, K2S2O5, RSO2H, RSO2Na and related compounds are discussed. Diverse mechanisms such as radical, electrophilic/nucleophilic addition, rearrangement, C-C bond cleavage, and CuAAC are discussed. The content is organized by substrates and reactivity patterns. We hope it will help in future research in this area.

Recent trends in the synthesis and applications of β-iodovinyl sulfones: a decade of progress

Direct vicinal difunctionalization of π-systems has emerged as a powerful platform for constructing multiple bonds in a single synthetic operation using simple chemical feedstocks. Over the past decade, there has been exponential growth in the direct construction of successive C-S and C-I bonds using a wide variety of sulfonyl and iodide reactants through 1,2-iodosulfonylation of alkynes in a regio- and stereo-selective manner. In this review, we mainly focus on the recent developments in the preparation of β-iodovinyl sulfones and their practical applications in organic synthesis. The most promising photoredox and electrochemical transformations for synthesizing β-iodovinyl sulfones are also reviewed. The multifunctional β-iodovinyl sulfones have recently been burgeoning as versatile synthetic precursors due to the combination of vinyl iodide and vinyl sulfone moieties, essential building blocks for diverse synthetic manipulations. We hereby present the chemistry of β-iodovinyl sulfones, which can be classified into numerous sections based on the sulfonyl surrogates, and potential synthetic approaches are systematically outlined.

Exploring the Divergent Reactivity of Vinyl Radicals Emanating from Alkynes and Thiols via Photoredox Catalysis

Organic chemistry has seen a surge in visible-light-driven transformations, which offer unique reaction pathways and access to new synthetic possibilities. We aim to provide a comprehensive understanding of state-of-the-art photo-mediated alkyne functionalization, with a focus on the reactive behavior of vinyl radicals. This review outlines our contributions to the field, including developing new methods for forming carbon-carbon and carbon-heteroatom bonds.

Syn-Selective Chlorosulfonylation of Alkynes via a Copper-Powder-Initiated Atom Transfer Radical Addition Reaction and Mechanistic Studies

Copper-powder-catalyzed syn-selective chlorosulfonylation of readily available alkynes by an atom transfer radical addition (ATAR) process has been developed, providing straightforward access to a broad range of (Z)-β-chlorovinylsulfones in good yields under mild conditions. In addition, this method is ligand-free and features excellent stereoselectivity and high atom economy. Moreover, the product was obtained without an apparent loss of yield when the reaction was performed on the gram scale at a low catalyst loading. In this reaction, the copper powder not only acts as a sulfone radical initiator but also produces the catalytically active CuCl species. Mechanistic investigations and DFT calculation studies revealed that the stereoselectivity is controlled by the thermodynamic stabilities of the in situ-generated cyclic alkenyl Cu^II complex intermediate, which can serve as a chlorine atom transfer agent.

Iodo-sulphonylation of 1,6-enynones: a metal-free strategy to synthesize N-substituted succinimides

An iodine-mediated radical cyclization of 1,6-enynones with sulphonyl hydrazides using tert-butyl hydroperoxide (TBHP) as the oxidant has been developed for the synthesis of iodo-sulphonylated-succinimide derivatives. The notable advantages of the developed method are metal-free conditions, broad functional group tolerance, column chromatography-free purification, high stereoselectivity (E isomer), shorter reaction times, and the cascade construction of three new bonds (C-S, C-I, and C-C). The synthetic application of the iodo-functionality has been extended to the Heck coupling reaction with acrylonitrile and to the Suzuki coupling reaction with benzene boronic acid.

Selective halocyclization and iodosulfonylation of N-benzothiazol2-yl alkynamides under mild conditions

An effective synthetic entry to pyrimidobenzothiazoles via 6-endo-dig halocyclization of N-benzothiazol-2-yl alkynamides was developed under mild conditions with a broad substrate scope. Several multisubstituted α,β-enones were synthesized by using the...

Copper-catalyzed switchable cyclization of alkyne-tethered α-bromocarbonyls: selective access to quinolin-2-ones and quinoline-2,4-diones

Copper-catalyzed cyclization of alkynes has played a significant role in modern catalytic chemistry.

Silver-promoted oxidative sulfonylation and ring-expansion of vinylcyclopropanes with sodium sulfinates leading to dihydronaphthalene derivatives

Silver-promoted sulfonylation and ring-expansion of vinylcyclopropanes with sodium sulfinates is established for the construction of 1-sulfonylmethylated 3,4-dihydronaphthalenes. This sulfonylation process involves a radical pathway, including sulfonyl radical formation, radical addition, ring-opening and cyclization. The 1-sulfonylmethylated 3,4-dihydronaphthalenes can be converted into other useful products.

An update on the use of sulfinate derivatives as versatile coupling partners in organic chemistry

The use of sulfinic acids and their salts continues to be extensively developed in organic chemistry. This is attributable to their dual capacity for acting as nucleophilic or electrophilic reagents, as well as their ease of preparation and stability on storage. This report highlights the research accomplished since 2015 on this topic, updating a previous review published by our team in 2014.

Base-controlled divergent synthesis of vinyl sulfones from (benzylsulfonyl)benzenes and paraformaldehyde

A tuneable metal-free protocol for the selective preparation of α-substituted vinyl sulfone and (E)-vinyl sulfone derivatives has been described. The base played an important role in the selectivity control of transformation.

I2-DMSO-H2O: A Metal-Free Combination System for the Oxidative Addition of Alkynes to Access (E)-α-Iodo-β-methylsulfonylalkenes

A simple and green reaction was discovered for iodization-methylsulfoxidation of alkynes to access (E)-α-iodo-β-methylsulfonylalkenes. This is the first report for the synthesis of iodovinyl methylsulfones by employing alkynes to react with molecular iodine (I₂), dimethyl sulfoxide (DMSO), and H₂O. Additionally, this protocol represents a new avenue for utilizing DMSO as the source of the -SO₂Me group and H₂O as the "O" source for the construction of the -SO₂Me group from DMSO, which is a valuable finding.

Metal-Free Synthesis of Functionalized Tetrasubstituted Alkenes by Three-Component Reaction of Alkynes, Iodine, and Sodium Sulfinates

An operationally simple, efficient, and metal-/peroxide-free three-component reaction of alkynes, iodine, and sodium sulfinates has been developed for the construction of highly functionalized tetrasubstituted alkenes. Iodo- and sulfonyl-containing tetrasubstituted alkenes, such as vinyl ketones, allylic alcohols, and conjugated enynes, could be obtained regio- and stereoselectively in up to 96% yield.

Metal-Free Vinyl C-H Sulfenylation/Alkyl Thiolation of Ketene Dithioacetals for the Synthesis of Polythiolated Alkenes

The sulfenylation of the vinyl C-H bond in ketene dithioacetals leading to the synthesis of polythiolated alkenes is achieved via the promotion of molecular iodine. In addition, alkyl thiols also exhibit tolerance to the C-H bond elaboration reaction for the synthesis of corresponding alkylthiolated ketene dithioacetals.

Iodine promoted iodosulfonylation of alkynes with sulfonyl hydrazides in an aqueous medium: highly stereoselective synthesis of (E)-β-iodo vinylsulfones

An efficient, molecular iodine-promoted MCR of alkynes and sulfonyl hydrazide for the synthesis of (E)-β-iodo vinylsulfone derivatives has been developed.

Nickel-Catalyzed Intermolecular Carbosulfonylation of Alkynes via Sulfonyl Radicals

β,β-Disubstituted vinyl sulfones were obtained with complete regio- and stereocontrol in a multicomponent reaction involving alkynes, organoboronic acids, and sulfonyl chlorides in the presence of a nickel catalyst. The reaction proceeds via sulfonyl radicals generated in situ under mild reaction conditions.

MnO2 -Promoted Oxidative Radical Sulfonylation of Haloalkynes with Sulfonyl Hydrazides: C(sp)-S Bond Formation towards Alkynyl Sulfones

A catalyst-free oxidative radical sulfonylation of haloalkynes with sulfonyl hydrazides is reported. It represents an example of C(sp)-S bond formation using sulfonyl hydrazides as sulfonyl radical sources. Various alkynyl sulfones were synthesized in moderate to good yields. Having MnO₂ as the oxidant is very critical for this transformation. Remarkably, the self-coupling reaction of haloalkynes through C(sp)-C(sp) bond formation is significantly inhibited under the standard reaction conditions.