Unsaturated Sulfones Research Articles

Catalytic Enantioselective Electrophilic Difunctionalization of Unsaturated Sulfones.

An efficient protocol of enantioselective thiolative azidation of sulfone-tethered alkenes via a chiral chalcogenide catalyzed electrophilic reaction is disclosed. A series of enantioenriched sulfones bearing remote stereogenic centers was achieved with good yields and high enantioselectivities with linear unsaturated sulfones and cyclic unsaturated sulfones. Mechanistic studies revealed the importance of the sulfone group in the improvement of the reactivity and enantioselectivity of the reaction.

Recent advances in the enantioselective synthesis of chiral sulfones via asymmetric hydrogenation.

Chiral sulfones are key structural motifs that extensively exist in natural products, drugs, and biologically active compounds. During the past few decades, rapid development has been made with respect to the highly enantioselective synthesis of chiral sulfones, in which the catalytic asymmetric hydrogenation of unsaturated sulfones provides an efficient and powerful methodology to construct chiral sulfones and their derivatives. This review highlights the progress achieved in transition metal (ruthenium, rhodium, iridium, and nickel) catalyzed direct asymmetric hydrogenation of a variety of unsaturated sulfones from the aspects of the substrate scope, catalytic mechanisms, and applications in the synthesis of biologically active molecules.

An Intramolecular Enyne Metathesis Approach for the Synthesis of Cyclic 3‐Substituted Unsaturated Sulfones

AbstractStudies into the ring‐closing enyne metathesis of a series of nine sulfone containing enynes is described. The readily accessible sulfone substrates were shown to undergo cyclisation to form 3‐subsituted 2,5‐dihydrothiophene 1,1‐dioxides (sulfolenes) and one 3,6‐dihydro‐2H‐thiopyran 1,1‐dioxide. The success of this process depended on the substrate's substitution pattern. Moderate to good yields of the products were obtained when the ene component was monosubstituted and it was found that the reactions proceeded most efficiently using the 2nd generation Grubbs catalysts, at elevated temperatures.

Photoredox Catalyzed Sulfonylation of Multisubstituted Allenes with Ru(bpy)3Cl2 or Rhodamine B

A highly regio- and stereoselective sulfonylation of allenes was developed that provided direct access to α, β-substituted unsaturated sulfone. By means of visible-light photoredox catalysis, the free radicals produced by p-toluenesulfonic acid reacted with multisubstituted allenes to obtain Markovnikov-type vinyl sulfones with Ru(bpy)3Cl2 or Rhodamine B as photocatalyst. The yield of this reaction could reach up to 91%. A series of unsaturated sulfones would be used for further transformation to some valuable compounds.

Recent Progress on the Synthesis of Chiral Sulfones.

Chiral sulfones extensively exist in drugs, agricultural chemicals, chiral organic intermediates, and functional materials. Their importance causes the rapid development of their synthetic methods in recent years. Many transition metal complex catalysts with chiral ligands and chiral organocatalysts are adopted in synthesis of chiral sulfones. Most of the methods to construct chiral sulfones are based on the reduction of unsaturated sulfones and the introduction of sulfone groups into unsaturated hydrocarbons. This review describes all classes of asymmetric reactions for synthesis of chiral sulfones.

Concise Synthesis of 1,1-Diarylvinyl Sulfones and Investigations on their Antiproliferative Activity via Tubulin Inhibition.

Discovery of small molecules that inhibit tubulin polymerization is an attractive strategy for the development of new and improved anti-proliferative agents. A series of novel 2-sulfonyl-1,1-diarylethenes were designed towards this end keeping in view the favorable chemical and pharmacological virtues of unsaturated sulfones. Rapid, convenient and efficient two-step assembly of the designed molecules was achieved by the vicinal iodo-sulfonylation-Suzuki coupling sequence. As hypothesized, these compounds showed good anti-proliferative activity against different tissuespecific cancer cell lines: MCF-7, DU-145, A-549, HepG2, and HeLa. The most active compound, pnitrophenyl ring-bearing analog, exhibited an IC50 value of 0.90μM against A-549 cells. Flow cytometry studies on this derivative revealed that it arrests the cell cycle of A-549 cells at the G2/M phase. This compound exhibited molecular binding to tubulin as well as tubulin polymerization inhibition comparable to that of colchicine. A new class of potent, tubulin binding anticancer agents based on 1,1,-diarylvinyl sulfone scaffold has been designed and synthesized.

The Role of Support Hydrophobicity in the Selective Hydrogenation of Enones and Unsaturated Sulfones over Cu/SiO2 Catalysts

The substitution of complex hydrides and Ni- and noble metal-based catalysts in the synthesis of pharma and fragrance products is a relevant topic in the green chemistry scenario. Here, we report that non-toxic, non-noble metal-based Cu/SiO2 catalysts are effective and very selective in the hydrogenation of α,β-unsaturated ketones, esters and sulfones under very mild conditions. Vanillyl acetone can be obtained in quantitative yield in 1 h at 90 °C and 1 bar of H2. High dispersion of the metallic phase and support wettability play a significant role in determining catalytic performance.

Highly Efficient Enantioselective Synthesis of Chiral Sulfones by Rh-Catalyzed Asymmetric Hydrogenation.

A highly efficient and enantioselective Rh-( R, R)-f-spiroPhos complex catalyzed hydrogenation of a series of unsaturated sulfones has been developed. With Rh-( R, R)-f-spiroPhos catalyst under mild conditions, not only the asymmetric hydrogenation of both the 3,3-diaryl and exocyclic α,β-unsaturated sulfones was first realized with up to 99.9% ee but also 3-alkyl-3-aryl and benzo[ b]thiophene-1,1-dioxides were successfully hydrogenated to the corresponding chiral sulfones with excellent enantioselectivities (up to 99.4% ee) regardless of the steric hindrance, electronic property, and geometry of the substrates. Moreover, this reaction offers a route to ( S)-(+)- ar-turmerone as a spice flavor, which is an important synthetic intermediate of pharmaceuticals.

Facile synthesis of biarylmethanes and tetrasubstituted arenes via a base-mediated [3 + 3] benzannulation reaction of Morita-Baylis-Hillman adducts and unsaturated sulfones.

A facile DBU-mediated [3 + 3] benzannulation reaction of 1,3-bis-sulfonyl propenes and Morita-Baylis-Hillman (MBH) bromides is described. The benzannulation reaction afforded bis-sulfonyl biarylmethanes/arenes with complete regioselectivity. The products may be converted readily into corresponding benzophenones via site-selective benzylic oxidation.

A Striking Reduction of Monoclonal Protein in a Patient with Concurrent Plasma Cell Dyscrasia and CMML-2, after Treatment with Rigosertib (01910.Na)

Rigosertib (ON 01910.Na) is a member of a broader class of unsaturated sulfone kinase inhibitors capable of inducing profound mitotic spindle abnormalities, abnormal centrosome localization, G2-M cell cycle phase arrest and mitotic catastrophe, culminating in apoptosis. Rigosertib is a Ras mimetic that interferes with phosphoinositide 3-kinase (PI-3K)/Akt, reactive oxygen species and Ras/Raf/polo-like kinase (PLK) signaling pathways. Although broadly cytotoxic against malignant cells, it is remarkably non-toxic for non-neoplastic cells. For this reason, this is a particularly attractive compound to test against neoplastic diseases of the bone marrow such as MDS and acute leukemia.This is a report of an unexpected reduction in monoclonal IgG, during a subject participation in a Phase III, randomized study of rigosertib, in patients with MDS who have either failed to respond, or progressed after receiving hypomethylating agents (ONTIME Trial).A 75-year-old man with CMML-2 had a CBC on day 1 of the trial that demonstrated leukocytosis, with absolute monocytosis, 7% blasts in the peripheral blood, Hgb of 9.4 gm/dl, and platelets of 7 K. He was transfusion dependent for both pRBCs and platelets. His chemistry panel demonstrated a high total protein of 9.9 (NL: 6.0 - 8.2 G/DL) with low albumin at 2.4 (NL: 3.5 - 5.0 G/DL); therefore, an SPEP/IPEP was performed, reporting the presence of monoclonal IgG kappa. Quantitative immunoglobulins showed an elevated IgG of 3594 mg/dl (NL: 596 - 1584 MG/DL). Serum free light chains were remarkable for an elevated Kappa fraction at 38.94 (NL: 0.33 - 1.94 MG/DL).On day 1 of cycle 5 of rigosertib, he was started on pulse decadron for 2 months, after which his disease progressed to AML, and he died shortly thereafter. Neither his bone marrow biopsies, nor his hematological parameters demonstrated a response to treatment with rigosertib.In contrast and interestingly, his total protein, serum kappa light chain load, and total IgG, all were drastically reduced shortly after initiation of rigosertib, as can be seen in the graph below depicting a substantial drop in his kappa light chain as well as the kappa/light chain ratio. Importantly, reduction in the monoclonal protein was noted prior to initiation of pulse decadron.Even though his initial bone marrow biopsy did not note a monoclonal plasma cell population, a subsequent bone marrow reported a low-level involvement with a plasma cell dyscrasia, with kappa light chain restriction. His final bone marrow biopsy confirmed progression to AML, but the previously seen plasma cell dyscrasia was no longer present.Conclusion: We are not aware of prior reports describing a similar effect of rigosertib on M-proteins. However, in vitro studies with rigosertib have demonstrated antitumor effects and induction of apoptosis in myeloma cell lines1. This observation merits further exploration of this agent in multiple myeloma.

Synthesis of the Tetrahydropyran Fragment of Bistramide D

AbstractA synthesis of the tetrahydropyran (THP) moiety of bistramide D has been completed by using cross‐metathesis and kinetically controlled intramolecular oxa‐Michael addition to form the ring with excellent trans selectivity. The C9 methyl substituent was introduced by using an unsaturated sulfone building block, which can be most effectively prepared through a combination of diastereoselective allylation and alkene isomerisation. The effect of this methyl group on subsequent cross‐metathesis reactions can be mitigated by careful choice of reaction conditions.

Enantioselective Synthesis of Chiral Sulfones by Ir-Catalyzed Asymmetric Hydrogenation: A Facile Approach to the Preparation of Chiral Allylic and Homoallylic Compounds

A highly efficient and enantioselective Ir-catalyzed hydrogenation of unsaturated sulfones was developed. Chiral cyclic and acyclic sulfones were produced in excellent enantioselectivities (up to 98% ee). Coupled with the Ramberg-Bäcklund rearrangement, this reaction offers a novel route to chiral allylic and homoallylic compounds in excellent enantioselectivities (up to 97% ee) and high yields (up to 94%).

ChemInform Abstract: Catalytic Asymmetric Conjugate Boration of α,β‐Unsaturated Sulfones.

AbstractThe asymmetric boration of unsaturated sulfones (I) and (III) in the presence of optically active Cu(I)‐diphosphine complexes followed by oxidation of the addition products with NaBO3 leads to corresponding β‐hydroxysulfones (II) and (IV) with high enantioselectivity.

ChemInform Abstract: Cycloaddition and Cyclization Reactions of Unsaturated Sulfones in Organic Synthesis

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ChemInform Abstract: 2,3-Dihalo-1-(phenylsulfonyl)-1-propenes as Versatile Reagents for the Synthesis of Annulated Furans and Cyclopentenones.

2,3-Dihalo-1-(phenysulfonyl)-1-propenes (DBP and DIP) are conveniently prepared by treating 1-(phenylsulfonyl)-1,2-propadiene with the appropriate halogen. These novel reagents undergo reaction with a variety of simple β-dicarbonyl anions to give substituted and annulated furans. When the reaction is carried out in polar solvents, 2,3,4-trisubstituted furans are formed. The reaction proceeds by an initial addition-elimination of the carbanion onto the vinyl carbon of the unsaturated sulfone which is followed by intramolecular ring closure on the enolate oxygen atom

ChemInform Abstract: Cascade Synthesis of New Aryl 2‐Phenylallyl Sulfones from α‐Methylstyrene and Aromatic Mono‐ and Bis‐Sulfonyl Chlorides.

AbstractAddition of arenesulfonyl chlorides to α‐methylstyrene is accompanied by an unexpected dehydrochlorination of the primary adducts furnishing unsaturated sulfones.

Formal Synthesis of (+)‐ and (–)‐Ferruginine

AbstractA formal synthesis of the naturally occurring (+)‐ferrugine and of its enantiomer starting from the commercially available tropinone is reported. The desymmetrization of tropinone was achieved through formation of diastereomeric unsaturated sulfoxides using the Andersen procedure. Introduction of the acetyl C(2) side chain was achieved by conjugate addition of lithiated ethyl vinyl ether to an unsaturated sulfone. N‐Boc‐Norferruginine, an advanced intermediate for the synthesis of ferruginine, was prepared in six steps and 19 % overall yield. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)

Metal-Catalyzed Oxidation and Epoxidation of α-Hydroxy Vinyl and Dienyl Sulfoxides

Treatment of acyclic alpha-hydroxyalkyl alpha,beta-unsaturated sulfoxides with t-BuOOH/VO(acac)2 results in rapid oxidation to the unsaturated sulfones followed by an unusual regio- and stereoselective epoxidation at the unsaturated sulfones; this methodology has been applied to the preparation of carbohydrate-like fragments.

Initiator efficiency in ATRP: the tosyl chloride/CuBr/PMDETA system

The low efficiency of p-toluenesulfonyl chloride (TsCl) initiator for the polymerization of methyl methacrylate (MMA), when used in conjunction with N, N, N′, N″, N″-pentamethyldiethylenetriamine (PMDETA) and CuBr under atom transfer radical polymerization (ATRP) conditions was investigated. A major by-product in the formation of poly(methyl methacrylate) was identified as N, N-dimethyl- p-toluenesulfonamide ( 5) and accounted for approximately half of the initiator. Compound 5 was shown to form by the direct reaction of PMDETA and TsCl. In a model experiment equimolar amounts of TsCl, PMDETA and CuBr reacted at 80°C in p-xylene resulted in the formation of 5 and two other unsaturated sulfones 2-methyl-3-[(4-methylphenyl)sulfonyl]-2-propenoic acid methyl ester ( 6) and 2-[[4-methylphenyl)sulfonyl]methyl]-2-propenoic acid methyl ester ( 7), formed by the dehydrohalogenation and subsequent isomerization of an intermediate chloro-adduct, 1-(4-methylbenzenesulfonyl)-2-chloro-2-(methyl)methyl propionate ( 2). Molecular modeling predicted the unsaturated sulfone 7 was thermodynamically more stable than the higher conjugated sulfone 6 and this was confirmed by the isomerization of 6 to 7 at room temperature under mild basic conditions. The absence of 6 and 7 in the polymerization of MMA under ATRP conditions showed that in the early stages of polymerization in the presence of excess MMA, the intermediate chloro-adduct 2 is not formed.

Reactions of Sulfenyl, Sulfinyl, and Sulfonyl Halides with Conjugated Dienes and Enynes. Synthesis of Unsaturated Sulfides, Sulfoxides, and Sulfones

The reactivities of sulfenyl, sulfinyl, sulfonyl halides in additions to conjugated dienes'enynes, and their derivatives are compared. Despite the fact that all these reactions involve cleavage offormally similar S-Cl bonds, the addition direction and rate depend on the structure of the reactants (dienes and enynes; organosulfur acid chlorides).