Chemicals from Alkynes with Palladium Catalysts

I2 -Catalyzed Cycloisomerization of Ynamides: Chemoselective and Divergent Access to Indole Derivatives

Herein, an I₂ -catalyzed unprecedented cycloisomerization of ynamides is developed, furnishing various functionalized bis(indole) derivatives in generally good to excellent yields with wide substrate scope and excellent atom-economy. This protocol not only represents the first molecular-iodine-catalyzed tandem complex alkyne cycloisomerizations, but also constitutes the first chemoselective cycloisomerization of tryptamine-ynamides involving distinctively different C(sp³ )-C(sp³ ) bond cleavage and rearrangement. Moreover, chiral tetrahydropyridine frameworks containing two stereocenters are obtained with moderate to excellent diastereoselectivities and excellent enantioselectivities. Meanwhile, cycloisomerization and aromatization of ynamides produce pyrrolyl indoles with high efficiency enabled by I₂ . Additionally, control experiments and theoretical calculations reveal that this reaction probably undergoes a tandem 5-exo-dig cyclization/rearrangement process.

Palladium-Catalyzed Cyclization Coupling with Cyclobutanone-Derived N-Tosylhydrazones: Synthesis of Benzofuran-3-Cyclobutylidenes and Spirocyclobutanes

A palladium-catalyzed cyclization coupling of iodoarene-tethered alkynes with cyclobutanone-derived N-tosylhydrazones is reported, providing a convenient and efficient approach to benzofuran-3-cyclobutylidenes. On this basis, spirocyclobutanes can be generated smoothly in an efficient cascade manner by the addition of dienophiles. Good yields and scalability are demonstrated. Sequential intramolecular carbopalladation, palladium-carbene migratory insertion, δ-hydride elimination, and cycloaddition processes are involved.

Rhodium-Catalyzed Remote Borylation of Alkynes and Vinylboronates

Remote functionalization involving a fascinating chain-walking process has emerged as a powerful strategy for the rapid access to value-added functional molecules from readily available feedstocks. However, the scope of current methods is predominantly limited to mono- and di-substituted alkenes. The remote functionalization of multi- and heteroatom-substituted alkenes is challenging, and the use of alkynes in the chain walking is unexplored. We herein report a rhodium catalyzed remote borylation of internal alkynes, offering an unprecedented reaction mode of alkynes for the preparation of synthetically valuable 1,n-diboronates. The regioselective distal migratory hydroboration of sterically hindered tri- and tetra-substituted vinylboronates is also demonstrated to furnish various multi-boronic esters. Synthetic utilities are highlighted through the selective manipulation of the two boryl groups in products such as the regioselective cross coupling, oxidation, and amination.

A flexible and wearable paper-based chemiresistive sensor modified with SWCNTs-PdNPs-polystyrene microspheres composite for the sensitive detection of ethylene gas: A new method for the determination of fruit ripeness and corruption

This study developed a flexible and wearable paper-based chemoresistive sensor (FWPCS) by modifying a SWCNT-PdNP-polystyrene microsphere (SPPM) composite (SPPM/FWPCS) for the low-cost and online determination of fruit ripeness and corruption. A new method for the batch and low-cost fabrication of SPPM/FWPCSs based on laser direct writing was proposed. The sensing mechanism of FWPCS relies on the electron depletion layer in the sensing composite created by the Schottky barriers among SWCNTs, PdNPs, and the adsorbed oxygen, along with the construction of O₂^-. When the SPPM sensing film is exposed to ethylene, trapped electrons are released into the conduction band through oxidation and cleavage of ethylene, causing a decrease in resistance. The properties and morphology of the synthesized SPPM composite were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Raman spectroscopy. Additionally, the key parameters for the fabrication of SPPMs/FWPCS related to the sensing performance were optimized. The concentration of C₂H₄ can be detected down to 100 ppb using the SPPMs/FWPCS at 25 °C. Finally, the real-time determination of banana ripeness and corruption verified the feasibility of the sensor, indicating that the SPPMs/FWPCS has prospects in monitoring fruit ripeness and corruption during storage and transportation.

Ag-NHC Complexes in the π-Activation of Alkynes

Silver-NHC (NHC = N-heterocyclic carbene) complexes play a special role in the field of transition-metal complexes due to (1) their prominent biological activity, and (2) their critical role as transfer reagents for the synthesis of metal-NHC complexes by transmetalation. However, the application of silver-NHCs in catalysis is underdeveloped, particularly when compared to their group 11 counterparts, gold-NHCs (Au-NHC) and copper-NHCs (Cu-NHC). In this Special Issue on Featured Reviews in Organometallic Chemistry, we present a comprehensive overview of the application of silver-NHC complexes in the p-activation of alkynes. The functionalization of alkynes is one of the most important processes in chemistry, and it is at the bedrock of organic synthesis. Recent studies show the significant promise of silver-NHC complexes as unique and highly selective catalysts in this class of reactions. The review covers p-activation reactions catalyzed by Ag-NHCs since 2005 (the first example of p-activation in catalysis by Ag-NHCs) through December 2022. The review focuses on the structure of NHC ligands and p-functionalization methods, covering the following broadly defined topics: (1) intramolecular cyclizations; (2) CO₂ fixation; and (3) hydrofunctionalization reactions. By discussing the role of Ag-NHC complexes in the p-functionalization of alkynes, the reader is provided with an overview of this important area of research and the role of Ag-NHCs to promote reactions that are beyond other group 11 metal-NHC complexes.

Stereospecific nickel-catalyzed [4+2] heteroannulation of alkynes with aminophosphanes

Enantioenriched phosphorus compounds play crucial roles in many fields ranging from catalyst to materials science to drug development. Despite advances in the construction of phosphacycles, incorporation of a P-chirogenic center into heterocycles remains challenging. Here, we report an effective method for the preparation of phosphacycles through nickel-catalyzed [4+2] heteroannulation of internal alkynes with aminophosphanes derived from o-haloanilines. Notably, chiral 2-λ5-phosphaquinolines can be prepared from P-stereogenic substrates via NH/PH tautomeric equilibrium without loss of stereochemical integrity. The strategy is found to exhibit a broad scope in terms of both reaction components, enabling modular construction of libraries of 2-λ5-phosphaquinolines with different steric and electronic properties for fine-tuning photophysical properties, where some of these compounds showed distinct fluorescence with high quantum yields. A series of mechanistic studies further shed light on the pathway of the heteroannulation and reasons for stereospecificity.

Problematic ArF-Alkynyl Coupling with Fluorinated Aryls. From Partial Success with Alkynyl Stannanes to Efficient Solutions via Mechanistic Understanding of the Hidden Complexity

The synthesis of aryl-alkynyl compounds is usually achieved via Sonogashira catalysis, but this is inefficient for fluorinated aryls. An alternative method reported by Shirakawa and Hiyama, using alkynylstannanes and hemilabile PN ligands, works apparently fine for conventional aryls, but it is also poor for fluorinated aryls. The revision of the unusual literature cycle reveals the existence and nature of unreported byproducts and uncovers coexisting cycles and other aspects that explain the reasons for the conflict. This knowledge provides a full understanding of the real complexity of these aryl/alkynylstannane systems and the deviations of their evolution from that of a classic Stille process, providing the clues to design several very efficient alternatives for the catalytic synthesis of the desired Ar^F-alkynyl compounds in almost quantitative yield. The same protocols are also very efficient for the catalytic synthesis of alkynyl-alkynyl' hetero- and homocoupling.

Selective Reductive Coupling of Vinyl Azaarenes and Alkynes via Photoredox Cobalt Dual Catalysis

A visible light-induced Co-catalyzed highly regio- and stereoselective reductive coupling of vinyl azaarenes and alkynes has been developed. Notably, Hünig's base together with simple ethanol has been successfully applied as the hydrogen sources instead of commonly used Hantzsch esters in this catalytic photoredox reaction. This approach has considerable advantages for the straightforward synthesis of stereodefined multiple substituted alkenes bearing an azaarene motif, such as excellent regioselectivity (>20 : 1 for >30 examples) and stereoselectivity (>20 : 1 E/Z), broad substrate scope and good functional group compatibility under mild reaction conditions, which has been utilized in the concise synthesis of natural product monomorine I. A reasonable catalytic reaction pathway involving protolysis of the cobaltacyclopentene intermediate has been proposed based on the mechanistic studies.

Nickel-catalyzed desulfonylative olefination of β-hydroxysulfones

A Ni-catalyzed C–O bond activation is used to access alkenes directly from β-hydroxysulfones.

Ru(ii)-catalysed oxidative (4 + 2) annulation of chromene and coumarin carboxylic acids with alkynes/propargylic alcohols: isolation of Ru(0) complexes

Ru(ii)-catalysed oxidative (4 + 2) annulation of chromene and coumarin carboxylic acids with alkynes affords pyrano-chromones via vinylic C–H bond activation; use of methyl-tethered propargylic alcohols instead of alkynes gives Ru(0) complexes.

E-selective Semi-hydrogenation of Alkynes under Mild Conditions by a Diruthenium Hydride Complex

The synthesis, characterization and catalytic activity of a new class of diruthenium hydrido carbonyl complexes bound to the tBu PNNP expanded pincer ligand is described. Reacting tBu PNNP with two equiv of RuHCl(PPh3 )3 (CO) at 140 °C produces an insoluble air-stable complex, which was structurally characterized as [Ru2 (tBu PNNP)H(μ-H)Cl(μ-Cl)(CO)2 ] (1) using solid-state NMR, IR and X-ray absorption spectroscopies and follow-up reactivity. A reaction with KOtBu results in deprotonation of a methylene linker to produce [Ru2 (tBu PNNP* )H(μ-H)(μ-OtBu)(CO)2 ] (3) featuring a partially dearomatized naphthyridine core. This enables metal-ligand cooperative activation of H2 analogous to the mononuclear analogue, [Ru(tBu PNP*)H(CO)]. In contrast to the mononuclear system, the bimetallic analogue 3 catalyzes the E-selective semi-hydrogenation of alkynes at ambient temperature and atmospheric H2 pressure with good functional group tolerance. Monitoring the semi-hydrogenation of diphenylacetylene by 1 H NMR spectroscopy shows the intermediacy of Z-stilbene, which is subsequently isomerized to the E-isomer. Initial findings into the mode of action of this system are provided, including the spectroscopic characterization of a polyhydride intermediate and the isolation of a deactivated species with a partially hydrogenated naphthyridine backbone.

Copper-Catalyzed Stereoselective Radical Phosphono-hydrazonation of Alkynes

A copper-catalyzed stereoselective phosphono-hydrazonation of terminal alkynes with alkyl carbazates and diarylphosphine oxides is described. This methodology provides facile access to a variety of β-hydrazonophosphine oxides in satisfactory yields. The reaction proceeds under mild conditions and exhibits good functional group tolerance. A mechanism featuring persulfate-mediated oxidative generation of phosphinoyl radicals and copper-assisted hydrazonation is proposed.

Base-Promoted Synthesis of Vinyl Sulfides from Sulfonium Triflates

A new protocol has been developed for vinyl sulfide synthesis promoted by an alkoxy base under metal-free conditions. In this reaction, aryl and alkenyl sulfonium triflates with diverse functionalities are converted into vinyl sulfides with excellent reactivity. This transformation features mild and safe reaction conditions that avoid catalyst, transition metal, high-pressure gas, and high reaction temperature without compromising efficiency.

Ru(II)-catalyzed external auxiliary-free primary amide-directed inverse Sonogashira reaction on (hetero)arylamides

Herein, we report ruthenium(II)-catalyzed weakly coordinating primary amide-assisted ortho-di-alkynylation of (hetero)arylamides via double C-H bond activation in the presence of bromo-alkynes as coupling partners. The attractive features of the developed strategy lie in the usage of an inexpensive ruthenium(II)-salt, external auxiliary-free directing group and simple reaction conditions, along with a broad substrate scope, high reaction yields and scale-up synthesis.

Photoinduced Remote C(sp3)-H Cyanation and Oxidation Enabled by a Vinyl Radical-Mediated 1,5-HAT Strategy

We report a vinyl radical-mediated 1,5-hydrogen atom transfer (1,5-HAT) strategy for the remote C(sp³)-H functionalization reaction, which includes cyanation, oxidation, and etherification under visible-light-induced photochemical conditions. This reaction is achieved using readily available alkyl N-hydroxyphthalimide esters as radical precursors, which can efficiently react with diverse alkynes to form key vinyl radical intermediates followed by a 1,5-HAT process. A series of structurally diverse γ-cyano, γ-carbonyl, and γ-oxygenated alkenes with excellent stereoselectivity can be efficiently constructed by this synthetic protocol.

Palladium-catalysed construction of butafulvenes

Butafulvene is a constitutional isomer of benzene, comprising a cyclobutene skeleton bearing two exocyclic conjugated methylene units. As a result of the intrinsic high strain energy and anti-aromaticity, the preparation of butafulvene compounds has been a fundamental issue for the development of butafulvene chemistry. Here an efficient palladium-catalysed coupling protocol involving propargylic compounds has been developed, providing a solid and versatile strategy for the rapid assembly of symmetric butafulvene derivatives. Based on mechanistic studies, two complementary mechanisms, both involving palladium catalysis, have been confirmed. With the mechanism unveiled, the synthesis of non-symmetric butafulvenes has also been achieved. Advantages of this strategy include tolerance to a wide range of propargylic molecules, mild reaction conditions, simple catalytic systems and easy scalability. The synthetic potential of the products as platform molecules for cyclobutene derivatives has also been demonstrated.

Ni-Catalyzed Reductive Arylalkenylation of Alkynes for the Selective Synthesis of Polysubstituted Naphthalenes

A Ni-catalyzed reductive arylalkenylation of alkynes with 1-bromo-2-(2-chlorovinyl)arenes in the presence of zinc powder has been developed. This base-free cyclization provides a novel protocol for the selective synthesis of 2-trifluoromethyl naphthalenes and ethyl 2-naphthoates from simple starting materials in moderate to good yields with excellent tolerance of functional groups.

Palladium(II)-Catalyzed [2+2+1] Annulation of Alkynes and Hydroxylamines: A Rodox-Neutral Approach to Fully Substituted Pyrroles

A palladium-catalyzed [2+2+1] annulation of alkynes and hydroxylamines has been developed for the rapid construction of fully substituted pyrroles. This transformation involves sequential nucleophilic-addition of hydroxylamine to alkyne, alkyne migratory insertion, and synergistic demetallization cyclization, which provides a redox-neutral annulation approach to pyrrole derivatives. Moreover, the strategy enabled alteration of the photophysical properties of pyrrole products by varying the aryl substituents, thus leading to the development of N-functionalized tetraarylpyrroles as new fluorophores.

Transition-Metal-Catalyzed Carbonylative Multifunctionalization of Alkynes

Currently, the construction of new carbon-carbon bonds and value-added structures in an atom- and step economical manner has become a continuous pursuit in the synthetic chemistry community. Since the first transition-metal-catalyzed hydroformylation of ethylene was reported by Otto Roelen in the 1930s, impressive progress has been achieved in the carbonylative functionalization of unsaturated C-C bonds. In contrast to alkenes, the carbonylative functionalization of alkynes offers tremendous potential for the construction of multisubstituted carbonyl-containing derivatives because of their two independently addressable π-systems. This review provides a timely and necessary investigation of transition-metal-catalyzed carbonylative mutifunctionalization of alkynes with the exclusion of carbonylative hydrofunctionalizations. Different transition metals including palladium, rhodium, iridium, ruthenium, iron, copper, etc. were applied to the development of novel carbonylative transformation. Various C-C, C-N, C-O, C-S, C-B, C-Si, and carbon-halogen bonds were formed efficiently and give the corresponding tri- or tetrasubstituted α,β-unsaturated ketones, diesters, and heterocycles.

Palladium-Catalyzed trans-Hydroalkoxylation: Counterintuitive Use of an Aryl Iodide Additive to Promote C–H Bond Formation

We report an enantioselective palladium-catalyzed trans-hydroalkoxylation of propargylic amines with a trifluoroacetaldehyde-derived tether to build chiral oxazolidines. Diastereoselective hydrogenation using a heterogeneous palladium catalyst then gave access to protected benzylic amino alcohols in 45–87% yields and 84–94% ee values. Hydroalkoxylation of the alkynes required a catalytic amount of aryl iodide, highlighting the counterintuitive key role played by a putative Pd(II)/ArI oxidative addition complex to promote oxypalladation/protodemetalation.

Surface-Plasmon-Enhanced Transmetalation between Copper and Palladium Nanoparticle Catalyst

Surface-plasmon-mediated phenylacetylide intermediate transfer from the Cu to the Pd surface affords a novel mechanism for transmetalation, enabling wavelength-tunable cross-coupling and homo-coupling reaction pathway control. C-C bond forming Sonogashira coupling and Glaser coupling reactions in O2 atmosphere are efficiently driven by visible light over heterogeneous Cu and Pd nanoparticles as a mixed catalyst without base or other additives. The reaction pathway can be controlled by switching the excitation wavelength. Shorter wavelengths (400-500 nm) give the Glaser homo-coupling diyne, whereas longer wavelength irradiation (500-940 nm) significantly increases the degree of cross-coupling Sonogashira coupling products. The ratio of the activated intermediates of alkyne to the iodobenzene is wavelength dependent and this regulates transmetalation. This wavelength-tunable reaction pathway is a novel way to optimize the product selectivity in important organic syntheses.

Directing group assisted rhodium catalyzed meta-C-H alkynylation of arenes

Site-selective C-H alkynylation of arenes to produce aryl alkynes is a highly desirable transformation due to the prevalence of aryl alkynes in various natural products, drug molecules and in materials. To ensure site-selective C-H functionalization, directing group (DG) assisted C-H activation has been evolved as a useful synthetic tool. In contrast to DG-assisted ortho-C-H activation, distal meta-C-H activation is highly challenging and has attracted significant attention in recent years. However, developments are majorly focused on Pd-based catalytic systems. In order to diversify the scope of distal meta-C-H functionalization, herein we disclosed the first Rh(i) catalyzed meta-C-H alkynylation protocol through the inverse Sonogashira coupling reaction. The protocol is compatible with various substrate classes which include phenylacetic acids, hydrocinnamic acids, 2-phenyl benzoic acids, 2-phenyl phenols, benzyl sulfonates and ether-based scaffolds. The post-synthetic modification of meta-alkynylated arenes is also demonstrated through DG-removal as well as functional group interconversion.

Simple and Expedient Access to Novel Fluorinated Thiazolo- and Oxazolo[3,2-a]pyrimidin-7-one Derivatives and Their Functionalization via Palladium-Catalyzed Reactions

An efficient, versatile, and one-pot method for the preparation of novel fluorinated thiazolo- and oxazolo[3,2-a]pyrimidin-7-ones is described from 2-aminothiazoles or 2-amino-oxazoles and fluorinated alkynoates. This transformation, performed under transition-metal-free conditions, offers new fluorinated cyclized products with good to excellent yields. Moreover, the functionalization of these N-fused scaffolds via the Suzuki-Miyaura and Sonogashira cross-coupling reactions led to the synthesis of highly diverse thiazolo- and oxazolo[3,2-a]pyrimidin-7-ones.

Reactions of [60]fullerene with alkynes promoted by OH. RSC Adv 2022;12:14018-14021. [PMID: 35548388 PMCID: PMC9087709 DOI: 10.1039/d2ra01300b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

In the current work, the reactions of [60]fullerene with alkynes promoted by OH⁻ (base) are addressed. The treatment of C₆₀ with alkynes in the presence of TBAOH produces alkynylation products (R-C₆₀–H) with high selectivity in o-DCB at 100 °C. Plausible reaction mechanisms were proposed. This work provides a convenient and environmental friendly method for the functionalization of fullerenes.

In the current work, the reactions of [60]fullerene with alkynes promoted by OH⁻ (base) are addressed. The treatment of C₆₀ with alkynes in the presence of TBAOH produces alkynylation products (R-C₆₀–H) with high selectivity in o-DCB at 100 °C.

LiCl-Mediated and Palladium-Catalyzed Oxidative Cyclization of Furan-Ynes via Dearomatizing Alkoxyalkenylation of Furan

A LiCl-mediated and palladium(II)-catalyzed oxidative cyclization of furan-ynes via dearomatizing alkoxyalkenylation of furan is reported to afford polyfunctionalized spiro-dihydrofurans with diastereospecification and high Z/E selectivity. This protocol is likely to involve chloropalladation of alkynes, subsequent intramolecular dearomatizing alkenylation of furan, and final O-allylation. The density functional theory (DFT) calculations demonstrated that the coordination of furan with dissolved Li⁺ weakens its nucleophilicity and promoted the Heck insertion, and dissolved Cl^- promoted chloropalladation of alkynes.

Cu(I)-Catalyzed C-H Alkenylation of Tertiary C(sp3)-H Bonds of 3-Aryl Benzofuran-2(3H)-ones to Give Z- and E-Styrene Containing Quaternary Carbon Centers with 99/1 Regioselectivity

The synthesis of isomerically pure olefins containing all-carbon quaternary centers is a challenging issue. Herein, we developed an efficient protocol for the synthesis of (Z)-olefins (27 examples, yield up to 97%, Z/E up to 99/1) and (E)-olefins (16 examples, yield up to 94%, E/Z up to 99/1) containing all-carbon quaternary centers. This protocol is adopted for the copper-catalyzed regioselective C-H alkenylation of the tertiary C(sp³)-H bond of 3-aryl benzofuran-2(3H)-ones with alkyne and alkenes. A diverse range of functional groups in the substrates is well-tolerated, such as F, Cl, Br, Me, OMe, ester, CF₃, etc. A gram scale experiment was performed in good yield, and the radical mechanisms are also proposed based on the control experiments.

Palladium-Catalyzed Tail-to-Tail Reductive Dimerization of Terminal Alkynes to 2,3-Dibranched Butadienes

The palladium-catalyzed tail-to-tail reductive dimerization of terminal alkynes is described for the first time. Aromatic terminal alkynes bearing diverse and sensitive functional groups as well as aliphatic terminal alkynes are efficiently transformed to 2,3-dibranched butadienes. The key to achieve a selective tail-to-tail reductive dimerization reaction is to control appropriately the acidity of the reaction solution, which is accomplished by a combined use of pivalic acid and para-toluenesulfonic acid. The tail-to-tail reductive dimerization reaction is proposed to proceed via a cationic alkenyl palladium intermediate under acidic conditions.

Cu-catalyzed, Mn-mediated propargylation and allenylation of aldehydes with propargyl bromides

A simple, practical, and high chemo-selective method for the synthesis of propargyl alcohol and allenyl alcohols via Cu-catalyzed, Mn-mediated propargylation and allenylation of aldehydes with propargyl bromides has been established. When 3-bromo-1-propyne was conducted under the standard condition, the aldehydes were transformed to the corresponding propargylation products completely, while when 1-bromo-2-pentyne was used, allenic alcohol was the only product. Variety of homopropargyl alcohols and allenyl alcohols were obtained in high yields and the reaction is compatible with broad substrate scopes. In addition, the large-scale reaction could also be proceeded smoothly indicating the potential synthetic applications of this transformation.

Noncovalent Interaction- and Steric Effect-Controlled Regiodivergent Selectivity in Dimeric Manganese-Catalyzed Hydroarylation of Internal Alkynes: A Computational Study

Selective hydroarylation of internal alkynes catalyzed by a dimeric manganese complex provides a powerful strategy for the construction of multisubstituted alkenes. In this work, density functional theory (DFT) calculations and experimental studies were carried out to explore the mechanism and origin of regiodivergent hydroarylation of internal alkynes reported by our group. The results demonstrate that this reaction first proceeds via a bimetallic mechanism to generate the active catalyst that subsequently undergoes a monometallic mechanism to run the three-stage catalytic cycle: alkyne migratory insertion, protonation, and active catalyst regeneration. Alkyne migratory insertion is considered as the regioselectivity-determining step. Energy decomposition analyses on insertion transition states suggest that the interaction between the substrate and catalyst is mainly responsible for the observed exclusive γ-selectivity of 1a, while the deformation of these two sections induced by the sterically hindered phenyl group and aryl group accounts for the complete β-position arylation of 1e. The decrease of γ-selectivity with the regulation of a tertiary alcohol motif in 1a originates from the reduced noncovalent interaction. The computational results provide important insights into the origin of regiodivergent selectivities and useful information for further designing and adjusting the strategy in Mn-catalyzed alkyne hydroarylation.

Ruthenafuran Complexes Supported by the Bipyridine-Bis(diphenylphosphino)methane Ligand Set: Synthesis and Cytotoxicity Studies

Mononuclear and dinuclear Ru(II) complexes cis-[Ru(κ²-dppm)(bpy)Cl₂] (1), cis-[Ru(κ²-dppe)(bpy)Cl₂] (2) and [Ru₂(bpy)₂(μ-dpam)₂(μ-Cl)₂](Cl)₂ ([3](Cl)₂) were prepared from the reactions between cis(Cl), cis(S)-[Ru(bpy)(dmso-S)₂Cl₂] and diphosphine/diarsine ligands (bpy = 2,2′-bipyridine; dppm = 1,1-bis(diphenylphosphino)methane; dppe = 1,2-bis(diphenylphosphino)ethane; dpam = 1,1-bis(diphenylarsino)methane). While methoxy-substituted ruthenafuran [Ru(bpy)(κ²-dppe)(C^O)]⁺ ([7]⁺; C^O = anionic bidentate [C(OMe)CHC(Ph)O]⁻ chelate) was obtained as the only product in the reaction between 2 and phenyl ynone HC≡C(C=O)Ph in MeOH, replacing 2 with 1 led to the formation of both methoxy-substituted ruthenafuran [Ru(bpy)(κ²-dppm)(C^O)]⁺ ([4]⁺) and phosphonium-ring-fused bicyclic ruthenafuran [Ru(bpy)(P^C^O)Cl]⁺ ([5]⁺; P^C^O = neutral tridentate [(Ph)₂PCH₂P(Ph)₂CCHC(Ph)O] chelate). All of these aforementioned metallafuran complexes were derived from Ru(II)–vinylidene intermediates. The potential applications of these metallafuran complexes as anticancer agents were evaluated by in vitro cytotoxicity studies against cervical carcinoma (HeLa) cancer cell line. All the ruthenafuran complexes were found to be one order of magnitude more cytotoxic than cisplatin, which is one of the metal-based anticancer agents being widely used currently.