Sulfoxonium Ylides Research Articles

Rh(III)‐Catalyzed C‐H Cyclization of 2‐Arylbenzimidazoles with CF3‐Imidoyl Sulfoxonium Ylides and Further Sc(III)‐Catalyzed Deaminative Hydroxylation

An efficient Rh(III)‐catalyzed C‐H bond activation/cyclization of 2‐arylbenzimidazoles with CF3‐imidoyl sulfoxonium ylides has been achieved, yielding diverse CF3‐ and amino‐disubstituted 5,6‐dihydrobenzoimidazo[2,1‐a]isoquinolines, which could undergo a deaminative hydroxylation to access CF3‐ and hydroxy‐disubstituted 5,6‐dihydrobenzoimidazo[2,1‐a]isoquinolines under Sc(OTf)3 catalyst. This developed strategy features easily available starting materials, broad substrate scope, ready scalability and high efficiency. Moreover, the antitumor activities of selected products against some human cancer cell lines were also investigated, and the results indicated that several products show the effective antiproliferative activities.

Catalytic Asymmetric C–H Activation/Cyclization of Sulfoximines with Sulfoxonium Ylides by a Chiral η6-Benzene Ruthenium(II) Catalyst

Catalytic Asymmetric C–H Activation/Cyclization of Sulfoximines with Sulfoxonium Ylides by a Chiral η⁶-Benzene Ruthenium(II) Catalyst

Base‐Mediated Cascade Reaction of CF3‐Imidoyl Sulfoxonium Ylides and Diimides for the Synthesis of Functionalized Amidines

AbstractA base‐mediated cascade reaction of CF3‐imidoyl sulfoxonium ylides (TFISYs) and diimides has been developed for the preparation of functionalized amidines. In the transformation, a cascade nucleophilic addition and subsequent [2,3]‐sigmatropic rearrangement of sulfoxonium ylide occur to enable an intramolecular migration of dimethyl sulfoxide (DMSO). The unexpected result of the developed protocol demonstrates the chameleonic reactivity of TFISYs.

Additive‐Free and Diastereoselective Synthesis for Trans‐Disubstituted‐2,3‐Dihydro‐Benzofurans via [4+1] Annulation between p‐QMs and TFISYs

AbstractAn additive‐free and diastereoselective [4+1] annulation between ortho‐hydroxyphenyl‐substituted para‐quinone methides and CF3‐substituted imidoyl sulfoxonium ylides is developed, providing a facile and practical route to diverse trans‐2,3‐dihydrobenzofurans with high efficiency. This protocol features mild conditions, broad substrate scope and easy to operate.

Construction of α‐ketoamides via Photoredox‐Catalyzed N−H Insertion of Amines by Sulfoxonium Ylides

Construction of α‐ketoamides via Photoredox‐Catalyzed N−H Insertion of Amines by Sulfoxonium Ylides

Divergent Synthesis of (CF3)‐Indazolo[3,2‐a]Isoquinolines with Potent Photophysical Property and Anticancer Activity from 3‐Aryl‐1H‐Indazoles and Sulfoxonium Ylides

AbstractTransition‐metal‐catalyzed inert C−H bond functionalization using sulfoxonium ylides as metal carbene surrogates to replace the explosive and labile diazo compounds is synthetically attractive. Presented herein is a divergent synthesis of (CF3)‐indazolo[3,2‐a]isoquinoline derivatives based on C−H bond activation‐initiated cascade reactions of 3‐aryl‐1H‐indazoles with sulfoxonium ylides. The formation of products involves Rh(III)‐catalyzed C(sp2)−H bond metalation, carbene formation, migratory insertion, proto‐demetalation and intramolecular condensation. In general, this newly developed protocol features simple substrates, structurally diverse products, step‐economy and scalability. In addition, evaluation of the photophysical properties and anti‐proliferative activity against three human cancer cell lines of the products thus obtained showed that some of them possess potent anticancer activity with potential self‐tracking capability through fluorescence detection.

Controlled Ru (II) & Rh (III) Catalyzed [4+2] & [4+1] Carbo‐Annulations via C−H Activation Using Sulfoxonium Ylide and Maleimide: Facile Access to Fused Benzoisoindole & Spiroindanone

AbstractA well‐ordered strategy of sulfoxonium ylides as a directing group as well as carbene source for the Ru‐catalysed [4+2] and Rh‐catalysed [4+1] carbo‐annulations with maleimides has been described. These novel methodologies have been successfully established for the synthesis of complex spiroindanones and benzoisoindoles containing compounds by the transition metal‐mediated C−H activation/functionalization reactions. Further, Rh‐catalysed [4+1] annulated compounds were obtained in the absence of any oxidant. A possible rationale for the remarkable divergent selectivity between the two catalysts has been proposed.

Remote Catalytic C(sp3)-H Alkylation via Relayed Carbenoid Transfer upon Olefin Chain Walking.

Transition metal carbenes have emerged as versatile intermediates for various types of alkylations. While reactions of metal carbene species with alkenes have been extensively studied, most examples focus on cyclopropanation and allylic C-H insertion. Herein, we present the first example of a catalytic strategy for the carbene-involved regioselective remote C-H alkylation of internal olefins by synergistically combining two iridium-mediated reactivities of olefin chain walking and carbenoid migratory insertion. The present method, utilizing sulfoxonium ylides as a bench-stable robust carbene precursor, was found to be effective for a series of olefins tethered with alkyl chains, heteroatom substituents, and complex biorelevant moieties. Combined experimental and computational studies revealed that reversible iridium hydride-mediated olefin chain walking proceeds to lead to a terminal alkyl-Ir intermediate, which then forms a carbenoid species for the final migratory insertion, resulting in regioselective terminal-alkylated products.

LiBr-Promoted Reaction of β-Ketodithioesters and Thioamides with Sulfoxonium Ylides to Synthesize Functionalized Thiophenes.

An operationally simple and highly efficient synthesis of functionalized thiophenes has been developed by LiBr promoted heteroannulation of β-ketodithioesters and thioamides with bench-stable sulfoxonium ylides in open air for the first time. This one-pot strategy involves formal Csp3-H bond insertion/intramolecular cyclization cascade, featuring readily accessible starting materials, TM and additive-free condition, broad substrate scope, high functional group compatibility, and scalability. Moreover, the carbonyl, thiomethyl, and amino groups in the resulting thiophene provide a good handle on downstream transformations.

Synthesis of α-Carbonyl-α'-sulfenyl Sulfoxonium Ylides in Water at Room Temperature.

An efficient synthesis of α-carbonyl-α'-sulfenyl sulfoxonium ylides through a KIO3-promoted cross-dehydrogenative coupling reaction of aryl thiols and α-carbonyl sulfoxonium ylides in an aqueous medium at room temperature has been described. The α-carbonyl sulfoxonium ylides and aryl thiols adorned with various functional groups were well-tolerated and afforded moderate to high yields of α-carbonyl-α'-sulfenyl sulfoxonium ylide derivatives. Finally, by converting synthesized ylide 3a into other valuable compounds, we demonstrated the practicality of this synthetic method.

Expanding the Library of Covalent Cysteine Cathepsin Probes Featuring Sulfoxonium Ylide Electrophiles.

Covalent activity-based probes are invaluable tools to monitor protease activity in vitro and in vivo. We recently discovered that dimethyl sulfoxonium ylides (SYs) bind selectively to cysteine cathepsin proteases in a mechanism-dependent manner. Herein, we present the synthetic routes and characterization of an expanded library of SY probes with a greater diversity in recognition sequences. The probes exhibit a range of potency and selectivity for the cathepsin family members. We also investigated the impact of fluorophore positioning on probes bearing P1 lysine. When sulfonated cyanine 5 was attached via the lysine side chain, the resulting probe was selective for cathepsin S. When attached to the α-amine, with the side chain amine either free or Boc-protected, the probes reacted with both cathepsin S and X. Bulk in the P1 position is thus well tolerated by cathepsin S but not cathepsin X. We examined the impact of Cy5 sulfonation on probe properties, demonstrating that unsulfonated probes exhibit greater cellular uptake, which affects their relative selectivity. Finally, we demonstrated that SY probes exhibit minimal labeling of cathepsin S in freshly prepared lysates, but this increases during the prolonged incubation of lysates. This work extends our understanding of SY probes and informs future probe development.

High-throughput experimentation and machine learning-promoted synthesis of α-phosphoryloxy ketones via Ru-catalyzed P(O)O-H insertion reactions of sulfoxonium ylides

High-throughput experimentation and machine learning-promoted synthesis of α-phosphoryloxy ketones via Ru-catalyzed P(O)O-H insertion reactions of sulfoxonium ylides

Carbene-Catalyzed [3 + 3] Annulation of Enals and Vinyl Sulfoxonium Ylides.

Carbene-catalyzed [3 + 3] annulation of enals and vinyl sulfoxonium ylides has been demonstrated. This method efficiently synthesizes a range of 2-sulfenylidene-3-cyclohexen-1-ones with high atom economy. Notably, the presence of the sulfoxonium ylide moiety in the obtained products significantly enhances their potential for further synthetic transformations.

The Acylation of α-Carbonyl Sulfoxonium Ylides with N-Hydroxyphthalimide Esters

AbstractA new method for the synthesis of 1,3-dicarbonyl sulfoxonium ylides is described. This acylation reaction is carried out under mild conditions using inexpensive and bench-stable N-hydroxyphthalimide esters as acylating agents. The reactions proceed via a non-radical, transition-metal-free pathway, and the corresponding products are obtained in yields of up to 85%.

Catalyst-Free [4+1] Annulation of α-Imidoyl Sulfoxonium Ylides and Diazo Compounds Enabling the Modular Synthesis of 2-Indanones and 3(2H)-Furanones.

A novel substrate-regulated [4+1] annulation of α-imidoyl sulfoxonium ylides with diazoketones under catalyst-free conditions is described. The reaction proceeds through a coupling of sulfoxonium ylides and in situ-generated ketenes to form the key reactive zwitterionic intermediates, followed by selective formation of C-C or C-O bonds to achieve five-membered ring systems. The cascade reaction permits the direct synthesis of synthetically useful 2-indanones and 3(2H)-furanones, which expands the reaction pattern of sulfoxonium ylides in annulation transformation.

Pragmatic Access to Hybrid Quinoxaline Scaffold Mediated by Elemental Sulfur Enabling Actualization to π-Extended and Aza-Annulated Heterocyclic Units.

A metal-free approach for synthesizing hybrid quinoxaline derivatives from sulfoxonium ylide and a 1,5-bis-nucleophilic N-heterocycle mediated by elemental sulfur is presented to illuminate the [5+1] cascade cyclization sequence. Large-scale synthesis and postsynthetic functionalizations for the annulative π-extension and intramolecular aza-annulation reactions reveal the potential utility and actualize the fabricated approach.

Asymmetric Synthesis of Chiral Cyclopropanes from Vinyl Sulfoxonium Ylides Catalyzed by a Chiral-at-Metal Rh(III) Complex.

A chiral-at-metal Rh(III) complex-mediated [2+1] cyclization of vinyl sulfoxonium ylides with α,β-unsaturated 2,2-acylimidazoles has been demonstrated for the first time. This work provides a practical approach for assembling 1,2,3-trisubstituted chiral cyclopropane with alkyl structural units, which had advantages such as a wide range of substrates, good functional group tolerance, and mild reaction conditions. In addition, further amplification experiments and transformation of cycloaddition products were carried out to highlight the practicality of the method.

Synthesis of N-Aryl-4-trifluoromethylthiazol-2-amines via Insertion/Annulation of Trifluoromethylimidoyl Sulfoxonium Ylides with Sodium Thiocyanate.

An efficient p-TsOH-mediated insertion of sodium thiocyanate into trifluoromethylimidoyl sulfoxonium ylides has been reported, affording annulated N-aryl-4-trifluoromethylthiazol-2-amines in 42-84% yields in a one-pot manner. This protocol encompasses a variety of trifluoromethylimidoyl sulfoxonium ylides with thiocyanate serving as the source of the "S-C═N" moiety of the thiazole ring. The versatile transformations of the resulting pharmacologically important N-aryl-4-trifluoromethylthiazol-2-amines were also demonstrated.

Elemental Sulfur‐Promoted Annulative Coupling of 2‐Aminobenzamides and 2‐Aminobenzylamines with Sulfoxonium Ylides: Access to Quinazolinones and Quinazolines

A novel and straightforward approach for synthesizing quinazolinones and quinazoline derivatives employing sulfur‐mediated annulative coupling of 2‐aminobenzamides and 2‐aminobenzylamines in conjunction with sulfoxonium ylides has been described. This method demonstrates a broad substrate range and exhibits excellent tolerance towards various functional groups. Finally, this protocol has been successfully applied to synthesize pyrazino‐fused quinazolinone derivative with adjustable fluorescence properties and tryptanthrin, a compound known for its potent antitubercular activity.

B(C6F5)3·H2O-Catalyzed N-H and C-H Functionalization of Aromatic Amines with Sulfoxonium Ylides under Metal-Free Conditions.

Hydrogen-bonded aggregates of B(C6F5)3 and water are proven as strong Brønsted acid catalysts, which have the advantages of low toxicity and broad compatibility. Sulfoxonium ylides are stable surrogates of diazo compounds, which participate in various reactions due to their versatile reactivity. Based on these characteristics, a strategy for C-N bond or C-C bond construction of aromatic amines with sulfoxonium ylides under metal-free catalytic conditions was established. This method has advantages of mild conditions and excellent yield, which is suitable for the N-H or C-H functionalization of various aromatic amine compounds.