Sulfur ylides

A keto-stabilized sulfur ylide, containing phthalazinedione fragment, was synthesized. During thermolysis, the ylide forms the product of intramolecular cyclization of pyrrolophthalazinedione structure. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2227–2229, November, 2007.     

Sulfur ylides 13. Synthesis and intramolecular cyclization of keto-stabilized sulfur ylides

Keto-stabilized sulfur mono-and bisylides were obtained from N-phthalylglutamic acid and their intramolecular cyclization was studied. The intramolecular cyclization of the ylide obtained at the α-carboxy group gave a product of the pyrrolizidinedione structure; bisylide yielded a cycloheptene derivative as the result of intramolecular recombination of intermediate dicarbene. The ylide obtained at the γ-carboxy group underwent no cyclization, giving methylthio ketone and oxo benzoate. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2771–2776, December, 2005.     

Sulfur ylides 8.* synthesis of 5-methylthio-7,8-dihydro-4,8a-diazfluorene-6,9-dione

Intramolecular cyclization of ketostabilized sulfur ylide obtained from β-alanine and 2,3-pyridinedicarboxylic anhydride was studied. The structure of the reaction product, 5-methylthio-7,8-dihydro-4,8a-diazafluorene-6,9-dione, was established by X-ray diffraction analysis. For Part 7, see Ref. 1. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2376–2378, November, 1998.     

Sulfur ylides. 5. Reactions of phthalimide-containing keto-stabilized sulfonium ylides

Some reactions of phthalimide-containing keto-stabilized sulfur ylides have been investigated. It was established that in addition to the formation of the usual products for keto-stabilized sulfur ylides, the reaction with acrylonitrile is accompanied by a rearrangement and leads to 1,1-disubstituted cyclopropanes.Institute of Chemistry, Bashkir Science Center, Urals Branch, Russian Academy of Sciences, 450054 Ufa. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 3, pp. 720–726, March, 1992.     

Sulfur ylides

The mass spectra of negative ions of keto-stabilized sulfur and phosphorus ylides (obtained from amino acids) and products of their thermal conversion are studied. The most characteristic peaks in the mass spectra of ylides belong to negative molecular ions and to [M−H]⁻ ions. Peaks of fragment ions in the mass spectra of ylides and products of their thermal conversion coincide both in mass numbers and resonance energies. For Part 8, see Ref. 1. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2100–2103, November, 1999.     

Sulfur ylides. 10. Modified method for the synthesis of pyrrolizine- and indolizinediones

A modified method for the synthesis of derivatives of pyrrolizinedione and indolizinedione was proposed. The method is based on the intramolecular cyclization of keto-stabilized sulfur ylides generated in situ from diazo ketones and Me₂S in the presence of Rh₂(OAc)₄.     

Sulfur ylides. 11. Selected chemical transformations of 1-methylthio-3,4-dihydropyrido[2,1-a]isoindole-2,6-dione

The reaction of 1-methylthio-3,4-dihydropyrido[2,1-a]isoindole-2,6-dione (2) with NaBH₄ led to reduction of the keto group to the hydroxy group. The reaction with the use of LiAlH₄ resulted in complete reduction of the carboximide group, reduction of the keto group to the hydroxy function, and reduction of the double bond accompanied by desulfurization. The reaction of indolizidinedione 2 with Zn afforded a reductive desulfurization product. The reactions of 2 with hydrazine hydrate, hydroxylamine, and formamide proceeded according to a mechanism typical of the keto group to give hydrazone, oxime, and the formyl derivative, respectively. Oxidation of the thiomethyl group of the starting compound with Bu^tOOH gave rise to sulfone or sulfoxide depending on the amount of the oxidizing agent used.     

Gold-catalyzed synthesis of furans and furanones from sulfur ylides

A golden switch: Doubly stabilized sulfonium ylides can be coupled with alkynes in a gold-catalyzed synthesis of heterocycles. This method hinges on a switch in the reactivity of the sulfur ylide resulting from the simple modification of the electron-withdrawing moieties and leads to either furans or furanones bearing a quaternary center.     

Sulfonium Ylides by (3+2) Cycloaddition of Arynes with Vinyl Sulfides: Stereoselective Synthesis of Highly Substituted Alkenes

The reaction of in situ generated arynes with vinyl sulfides provides benzannulated sulfonium ylides in a (3+2) cycloaddition. Trapping of the intermediate ylides with electrophiles (proton transfer or a second aryne addition) and subsequent β‐elimination give rise to di‐, tri‐, or tetrasubstituted alkenes with high stereoselectivity. Experimental studies and DFT calculations provide insight into the mechanisms of these cascade reactions.     

Quantum chemical study of the effect of N,N-acyl group nature on the structure and Gibbs free energy of the sulfur ketoylides and products of their transformations

With the purpose to study the effect of the nature of the imido-group of N,N-acyl-protected β-methyl-substituted keto-stabilized sulfonium ylides on the formation of methylthiopyrrolisinediones by cyclization, the structure features of these ylides are investigated by ab initio methods. The imido-group nature is shown to insignificantly affect in most cases the structure and the relative free energy of conformers of the ketoylides in question and the products of a cyclization reaction with their participation. The energy difference between the anti-peri-planar and syn-clinal orientation of nitrogen atoms in the imido-group and ylide carbon atom is negligible. The latter orientation is necessary for the reaction of intramolecular cyclization to proceed because in this case carbon atoms between which the bond forms are drawn together. The structure of cyclic pentanomial N,N-acyl group slightly affects the calculated values of Gibbs free energy of sulfur ketoylide reactions, and a temperature increase promotes the intramolecualr cyclization reactions. Wittig and Corey-Chaykovsky reactions typical of ylides are the least thermodynamically favorable for the sulfonium ketoylides under study.     

Enantioselective Intramolecular [2,3]-Sigmatropic Rearrangement of Aldehydes via a Sulfonium Enamine Intermediate

The rearrangement of sulfur-containing aldehydes by using a sulfonium enamine intermediate as a formylcarbene mimetic is reported. This is an enantioselective, organocatalytic [2,3]-sigmatropic rearrangement enabling chiral cyclic sulfides bearing an α-quaternary chiral center to be prepared in high optical purity. The enantioselectivity is controlled with a cooperative organocatalyst pair consisting of a chiral amine and a chiral phosphoric acid (CPA). The synthetic versatility of this method is demonstrated by its rapid access to structurally diverse chiral spiro S-heterocycles.     

New synthesis of the dihydroindolizinoquinoline system by intramolecular cyclization of sulfur ylide

An efficient method is proposed for obtaining the dihydroindolizinoquinoline system by intramolecular cyclization of keto-stabilized sulfonium ylide obtained from -alanine and quinoline-2,3-dicarboxylic acid anhydride.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1813–1816, December, 2004.     

Reactions of distabilized β-dicarbonyl sulfonium and iodonium ylides with isocyanates

The reactions of tosyl isocyanate with diethyl diphenylsulfuranylidenemalonate, 2-dimethylsulfuranylidenedimedone, and 2-dimethylsulfuranylideneindane-1,3-dione afforded 1,3-ditosyl-5,5-diethoxycarbonylimidazolidine-2,4-dione and tosylimination products at the keto groups, respectively. Phenyliodonium ylides derived from diethyl malonate and ethyl acetate react with 3,4-dichlorophenyl isocyanate to form substituted oxazolin-2-ones. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 854–861, May, 2006.     

One-pot synthesis of stable phosphonium ylides using 2-aminothiophenol

Protonation of reactive 1:1 intermediates produced in the reaction between triphenylphosphine and dialkyl acetylenedicarboxylate by 2-aminothiophenol leads to vinylphosphonium salts, which undergo Michael addition with thiophenolate anion to produce highly functionalized phosphonium ylides in excellent yields.     

A versatile method for the synthesis of substituted 1-aminohydantoin derivatives

An efficient and versatile method has been developed for the synthesis of 1-aminohydantoin derivatives which can be substituted at all the possible positions of the hydantoin ring. The starting materials are aldehydes, ketones, carboxylic acids and hydrazides as well as isocyanates readily available from commercial sources. The semicarbazide-type reaction product of an N-acyl-N′-(1-cyanoalkyl)hydrazine, obtained from the above materials by methods known from the literature, and an isocyanate is cyclized in the presence of a basic catalyst to yield 1-acylamino-4-imino-2-oxoimidazolidine derivatives whose acid catalyzed hydrolysis leads to 1-aminohydantoin derivatives in good to excellent yields. The last two steps are carried out in a single reaction medium.     

On Silylated Oxonium and Sulfonium Ions and Their Interaction with Weakly Coordinating Borate Anions

Attempts have been made to prepare salts with the labile tris(trimethylsilyl)chalconium ions, [(Me₃Si)₃E]⁺ (E=O, S), by reacting [Me₃Si-H-SiMe₃][B(C₆F₅)₄] and Me₃Si[CB] (CB⁻=carborate=[CHB₁₁H₅Cl₆]⁻, [CHB₁₁Cl₁₁]⁻) with Me₃Si-E-SiMe₃. In the reaction of Me₃Si-O-SiMe₃ with [Me₃Si-H-SiMe₃][B(C₆F₅)₄], a ligand exchange was observed in the [Me₃Si-H-SiMe₃]⁺ cation leading to the surprising formation of the persilylated [(Me₃Si)₂(Me₂(H)Si)O]⁺ oxonium ion in a formal [Me₂(H)Si]⁺ instead of the desired [Me₃Si]⁺ transfer reaction. In contrast, the expected homoleptic persilylated [(Me₃Si)₃S]⁺ ion was formed and isolated as [B(C₆F₅)₄]⁻ and [CB]⁻ salt, when Me₃Si-S-SiMe₃ was treated with either [Me₃Si-H-SiMe₃][B(C₆F₅)₄] or Me₃Si[CB]. However, the addition of Me₃Si[CB] to Me₃Si-O-SiMe₃ unexpectedly led to the release of Me₄Si with simultaneous formation of a cyclic dioxonium dication of the type [Me₃Si-μO-SiMe₂]₂[CB]₂ in an anion-mediated reaction. DFT studies on structure, bonding and thermodynamics of the [(Me₃Si)₃E]⁺ and [(Me₃Si)₂(Me₂(H)Si)E]⁺ ion formation are presented as well as mechanistic investigations on the template-driven transformation of the [(Me₃Si)₃E]⁺ ion into a cyclic dichalconium dication [Me₃Si-μE-SiMe₂]₂²⁺.     

Reactive polymer zwitterions: Sulfonium sulfonates

Sulfonium sulfonate, or sulfothetin, zwitterionic monomers were synthesized by ring‐opening of 1,3‐propanesultone with dialkyl sulfides containing styrenic or methacrylic moieties. Reversible addition‐fragmentation chain‐transfer polymerization of these monomers was achieved in water or trifluoroethanol, and the resulting polymers exhibited higher upper critical solution temperatures than the analogous sulfobetaine polymers. Unlike typical polymer zwitterions, these polymeric sulfothetins possess an inherent reactivity that proved tunable based on their chemical structures. This reactivity makes them amenable to post‐polymerization modification by nucleophilic dealkylation to rapidly access novel substituted polymers and gels. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 83–92     

(4-苯硫基-苯基)二苯基硫鎓六氟磷酸盐的合成研究

以P₂O₅为脱水剂,甲烷磺酸为溶剂,二苯亚砜与二苯硫醚反应制备了(4-苯硫基-苯基)二苯基硫六氟磷酸盐.对产物进行了元素分析、紫外光谱、红外光谱、气-质联用和核磁共振的结构确证.该硫盐对环氧树脂具有良好的固化性能.     

Sulfonium ylides derived from 2-hydroxy-benzoquinones: crystal and molecular structure and their one-step conversion into Mannich bases by amine N-oxides

Reaction of 2-hydroxy-para-benzoquinones with DMSO/Ac₂O produced dimethylsulfonium ylides, of which crystal structures as well as solid and liquid state NMR spectra were recorded. The ylides react with tertiary methylamine N-oxides in a one-pot, multi-step process to 3-methylamino-substituted benzoquinones. The mechanism starts with a deoxygenative deprotonation of the amine N-oxides, followed by a formal electrophilic displacement of DMSO by the resulting carbonium-iminium ion.