- Reductive Lithiation of Bis-Phenylsulfones
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Reductive cleavage of geminal bis-phenylsulfones using lithium naphthalenide in THF at -78 degC selectively affords α-sulfonyl carbanions which participate in typical reaction with electrophiles. - Key words: desulfonylation, lithium naphthalenide, alkyla
- Mioskowski, Charles
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- Base-Mediated Radical Borylation of Alkyl Sulfones
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A practical and direct method was developed for the production of versatile alkyl boronate esters via transition metal-free borylation of primary and secondary alkyl sulfones. The key to the success of the strategy is the use of bis(neopentyl glycolato) diboron (B2neop2), with a stoichiometric amount of base as a promoter. The practicality and industrial potential of this protocol are highlighted by its wide functional group tolerance, the late-stage modification of complex compounds, no need for further transesterification, and operational simplicity. Radical clock, radical trap experiments, and EPR studies were conducted which show that the borylation process involves radical intermediates.
- Huang, Mingming,Hu, Jiefeng,Krummenacher, Ivo,Friedrich, Alexandra,Braunschweig, Holger,Westcott, Stephen A.,Radius, Udo,Marder, Todd B.
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- Method for synthesizing sulfone compounds under photocatalysis condition
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The invention belongs to the technical field of compound preparation, and particularly relates to a method for synthesizing sulfone compounds under a photocatalysis condition. Aromatic hydrazine and sulfinate are used as raw materials, and under the action of alkali and a solvent, a sulfone compound is generated through reaction under the condition of air or oxygen under the illumination of visible light. According to the method disclosed by the invention, aryl hydrazine is used as an arylation reagent, polyacid salt is used as a catalyst or an organic photosensitizer is used as a catalyst, and the sulfones compound can be efficiently synthesized by coupling with sulfinate under the condition of room temperature through visible light irradiation. The method has good substrate universalityand relatively mild reaction conditions, is not only a substitute for synthesizing sulfone compounds by coupling from simple substrates reported at present, but also broadens the new application of the polyacid salt in the field of photocatalysis.
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Paragraph 0174-0178
(2021/03/31)
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- Green Organocatalytic Oxidation of Sulfides to Sulfoxides and Sulfones
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A highly efficient synthetic methodology towards the selective synthesis of sulfoxides and sulfones is reported using a cheap and green organocatalytic method. Starting from sulfides and using 2,2,2-trifluoroacetophenone as the organocatalyst and H2O2 as the oxidant, the high-yielding preparation of sulfoxides or sulfones is described, being dependent on the reaction conditions.
- Voutyritsa, Errika,Triandafillidi, Ierasia,Kokotos, Christoforos G.
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p. 917 - 924
(2017/02/15)
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- Iron-catalyzed cross-coupling of unactivated secondary alkyl thio ethers and sulfones with aryl grignard reagents
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The first systematic investigation of unactivated aliphatic sulfur compounds as electrophiles in transition-metal-catalyzed cross-coupling are described. Initial studies focused on discerning the structural and electronic features of the organosulfur substrate that enable the challenging oxidative addition to the C(sp3)-S bond. Through extensive optimization efforts, an Fe(acac)3-catalyzed cross-coupling of unactivated alkyl aryl thio ethers with aryl Grignard reagents was realized in which a nitrogen "directing group" on the S-aryl moiety of the thio ether served a critical role in facilitating the oxidative addition step. In addition, alkyl phenyl sulfones were found to be effective electrophiles in the Fe(acac) 3-catalyzed cross-coupling with aryl Grignard reagents. For the latter class of electrophile, a thorough assessment of the various reaction parameters revealed a dramatic enhancement in reaction efficiency with an excess of TMEDA (8.0 equiv). The optimized reaction protocol was used to evaluate the scope of the method with respect to both the organomagnesium nucleophile and sulfone electrophile.
- Denmark, Scott E.,Cresswell, Alexander J.
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p. 12593 - 12628
(2014/01/17)
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- Catalytic enantioselective oxidation of bulky alkyl aryl thioethers with H2O2 over titanium-salan catalysts
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A simple and efficient catalytic procedure for the oxidation of bulky (preferably aryl benzyl substituted) thioethers with hydrogen peroxide in good to high yields and enantioselectivities (up to 98.5%ee) is reported. The high optical yields are achieved in a tandem stereoconvergent enantioselective oxidation and kinetic resolution process. A reasonable balance between the sulfoxide yield and enantioselectivity could be found by varying the concentration and temperature. An improved synthesis of the titanium-salan catalysts for the preparation of a more stereoselective catalyst is reported.
- Bryliakov, Konstantin P.,Talsi, Evgenii P.
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p. 4693 - 4698
(2011/10/03)
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- Experimental and theoretical investigation of the enantiomerization of Lithium α-tert-butylsulfonyl carbanion salts and the determination of their structures in solution and in the crystal
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Dynamic NMR (DNMR) spectroscopy of [R1C(R2)SO 2R3]Li (R1, R2 = alkyl, phenyl; R3 = Ph, tBu, adamantyl, CEt3) in [D8]THF has shown that the S-tBu, S-adamantyl, and S-CEt3 derivatives have a significantly higher enantiomerization barrier than their S-Ph analogues. C α-S bond rotation is most likely the rate-determining step of the enantiomerization of the salts bearing a bulky group at the S atom and two substituents at the Cα atom. Ab initio calculations on [Me(Ph)- SO 2tBu]- gave information about the two Cα-S rotational barriers, which are dominated by steric effects. Cryoscopy of [R1C(R 2)SO2tBu]Li in THF at -108°C revealed the existence of monomers and dimers. X-ray crystal structure analysis of the monomers and dimers of [R1C(R2)SO2tBu]Li·L n (R1 = Me, Et, tBuCH2, PhCH2, tBu; R2 = Ph, L = THF, 12-crown-4, PMDTA) and [R1C(R 2)SO2Ph]Li·2diglyme [R1 = R2 = Me, Et; R1-R2 = (CH2)5] showed them to be O-Li contact ion pairs (CIPs). The monomers and dimers have a Cα-S conformation in which the lone-pair orbital at the Cα atom bisects the O-S-O angle and a significantly shortened Cα-S bond. The Cα atom of [R1C(R2)SO2R 3]Li·Ln (R1 = Ph; R3 = Ph, tBu) is planar, whereas the Cα atom of [R1C(R 2)SO2R3]Li·Ln (R1 = R2 = alkyl) is strongly pyramidalized in the case of R3 = Ph and most likely planar for R3 = tBu. Ab initio calculations on [MeC- (Me)SO2R]- gave a pyramidalized Cα atom for R = Me and a nearly planar one for R = CF3 and tBu. The [R1C(R 2)SO2-tBu]Li salts were characterized by 1H, 13C, and 6Li NMR spectroscopy. 1H{ 1H} and 6Li{1H} NOE experiments are in accordance with the existence of O-Li CIPs. 1H and 13C NMR spectroscopy of [R1C(R2)SO2tBu]Li in [D 8]THF at low temperatures showed equilibrium mixtures of up to five different species being most likely monomeric and dimeric O-Li CIPs with different configurations. According to 7Li NMR spectroscopy, the addition of HMPA to [MeC(Ph)SO2tBu]Li in [D8]THF at low temperatures causes the formation of the separated ion pair [MeC(Ph)SO 2tBu]Li(HMPA)4.
- Scholz, Roland,Hellmann, Gunther,Rohs, Susanne,Raabe, Gerhard,Runsink, Jan,Oezdemir, Diana,Luche, Olaf,Hess, Thomas,Giesen, Alexander W.,Atodiresei, Juliana,Lindner, Hans J.,Gais, Hans-Joachim
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supporting information; experimental part
p. 4559 - 4587
(2010/10/19)
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- Catalyst-free alkylation of sulfinic acids with sulfonamides via sp 3 C-N bond cleavage at room temperature
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An unprecedented catalyst-free alkylation of sulfinic acids with sulfonamides has been developed via sp3 C-N bond cleavage at room temperature. In the absence of external catalysts and additives, a wide variety of N-benzylic and N-allylic sulfonamides couple with sulfinic acids to give structurally diversified sulfones in moderate to excellent yields. Furthermore, the reaction of N-(2-acyl)allylic sulfonamides with sulfinic acids provides a convenient access to trisubstituted allyl sulfones with exclusive Z selectivity.
- Liu, Cong-Rong,Li, Man-Bo,Cheng, Dao-Juan,Yang, Cui-Feng,Tian, Shi-Kai
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supporting information; experimental part
p. 2543 - 2545
(2009/10/10)
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- WO3-30% H2O2-cinchona alkaloids: A new heterogeneous catalytic system for the asymmetric oxidation of sulfides and the kinetic resolution of racemic sulfoxides
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WO3-catalyzed asymmetric oxidation of thioethers and kinetic resolution of sulfoxides with 30% aq. H2O2 in the presence of cinchona alkaloids under heterogeneous conditions affords chiral sulfoxides in high yields with moderate to good enantioselectivities.
- Thakur, Vinay V.,Sudalai
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p. 407 - 410
(2007/10/03)
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- A novel method for the synthesis of aryl sulfones
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New sulfones were produced from aryl trifluoromethyl sulfones and Grignard reagents in good to high yields. The advantage of this transformation over a previous method by which sulfones were prepared from sulfonyl fluorides and organometallic reagents is discussed.
- Steensma, Ruo W.,Galabi, Sharen,Tagat, Jayaram R.,McCombie, Stuart W.
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p. 2281 - 2283
(2007/10/03)
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- Use of 2,3-Bis(phenylsulfonyl)-1-propene as a Multicoupling Reagent
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2,3-Bis(phenylsulfonyl)-1-propene (1) reacts with various amines to afford products derived from addition across the double bond as well as SN2' displacement.When treated with 2-piperidinemethanol, bissulfone 1 gave the expected SN2'
- Padwa, Albert,Kline, Donald N.,Murphree, S. Shaun,Yeske, Philip E.
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p. 298 - 306
(2007/10/02)
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- The samarium grignard reaction. In situ formation and reactions of primary and secondary alkylsamarium(III) reagents
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This work shows that primary and secondary radicals are rapidly reduced in THF/HMPA to form primary- and secondary-alkylsamarium reagents. The primary- and secondary-radicals can be formed either by direct SmI2 reduction of primary- and secondary-halides or by a previous rapid radical cyclization. The samarium reagents have moderate stability in solution, and they react with a variety of typical electrophiles, including aldehydes and ketones. The work further shows that organosamarium intermediates can be involved in the traditional samarium Barbier reaction of aldehydes and ketones conducted in THF/HMPA. A new procedure called the "samarium Grignard" method is introduced, and it is suggested that this new procedure will have considerably more scope and generality than the samarium Barbier reaction.
- Curran, Dennis P.,Totleben, Michael J.
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p. 6050 - 6058
(2007/10/02)
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- Scope and limitations in the use of α-silyl and α-stannyl sulfones as latent α-sulfonyl anions
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Three methods for the regeneration of α-sulfonyl anions from α-silyl sulfones and α-stannyl sulfones are investigated. These methods include: (1) treatment of α-silyl sulfones with electrophiles (aldehydes and acid halides) in the presence of fluoride ion; (2) reaction of α-silyl sulfones with n-butyllithium which produces an α-silyl anion via a migration of the -SiMe3 group from the α-position to the ortho-position of the phenyl sulfones; and (3) direct transmetalation of α-stannyl sulfone by treatment with n-butyllithium. The addition of cerium [III] chloride is shown to substantially decrease enolization problems associated with addition of α-sulfonyl anions to carbonyl compounds bearing enolizable protons.
- Lamothe,Anderson,Fuchs
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p. 1675 - 1693
(2007/10/02)
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- Intramolecular Acylation of an α-Sulfonyl Anion Generated via Halogen-metal Exchange of an α-Halosulfone Bearing an Unsymmetrical Anhydride
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α-Halosulfones are useful for the in situ preparation of α-sulfonyl anions in the presence of acylating agents bearing enolizable protons.Inter- and intramolecular acylations can be effected by halogen-metal exchange at low temperature.
- Anderson, M. B.,Lamothe, M.,Fuchs, P. L.
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p. 4457 - 4460
(2007/10/02)
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- Synthesis of Tertiary Alcohols via the Use of the Allyldimethylsilyl Moiety as a Latent Hydroxyl Group in the Kumada-Fleming-Tamao Reaction
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The phenyldimethylsilyl to hydroxyl transformation fails in the cases where a cyclic tertiary carbon center is involved as was observed in the synthesis of phorbol C-ring models.An alternate functionality in the form of allyldimethylsilane (ADMS) is found to work well in these and other cases involving tertiary centers.With proper choice of reagents, the ADMS group can be employed as a latent alcohol in systems containing ketones, esters, arenes, and vinyl groups.
- Magar, Sharad S.,Fuchs, P. L.
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p. 7513 - 7516
(2007/10/02)
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- Synthesis of vinylic and cyclic sulfones via a radical addition-elimination sequence
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Radical attack on the double bond of 2,3-bis(phenylsulfonyl)-1-propene leads to an intermediate sulfonyl stabilized radical. This species readily fragments to produce a new vinyl sulfone which can undergo further radical cyclization to give a six ring sul
- Padwa, Albert,Shaun Murphree,Yeske, Philip E.
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p. 2983 - 2986
(2007/10/02)
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- Unusual Two-Bond 13C,13C Coupling Constants in Sulphones
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A measurable coupling between carbon atoms through the SO2 group is observed in a series of structurally diverse sulphones.In open-chain (single coupling path) sulphones this 2J coupling ranges from 5.5 to 27.2 Hz, while in cyclic (multiple coupling path) sulphones values ranging from 4.3 to 21.6 Hz are observed.Sulphides and sulphoxides do not exhibit a corresponding coupling of comparable magnitude.A positive sign for this coupling is derived from the data of cyclic sulphones.Whereas substituents and branching at the coupling termini exert minor influences on the coupling, the most important factor determining the magnitude of the 2J(CSC) coupling is the hybridization of the coupling carbon atoms.A linear relationship between the 2J value and the s character product of the C-S bond forming C orbitals is established.KEY WORDS Sulphones 13C NMR Geminal 13C,13C coupling
- Ruecker, Christoph,Fritz, Hans
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p. 1103 - 1108
(2007/10/02)
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- The Synthesis of Ketones via α-Silyl Sulphides
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α-Phenylthiosilanes (2) have been prepared by alkylation of the anion (4) derived from the 1-phenylthio-1-trimethylsilylalkane (1).These anions (4) have benn prepared by a variety of methods including, direct deprotonation of (1), displacement of a phenylthio group by lithium naphthalenide addition of an alkyl-lithium to 1-phenylthio-1-trimethylsilylethene (7), and transmetallation of a tributylstannyl moiety.The formation of an alkyl-lithium by reaction of lithium naphthalenide with a phenyl sulphide provided an additional route to (2) from bis(phenylthio)acetals (8).An alternative path to the α-phenylthiosilanes (2) was to reduce the corresponding α-phenylsulphonylsilane (15); these, in turn, being readily available from alkylation or silylation of α-sulphonyl anions.The α-phenylthiosilanes (2) were converted into the O-trimethylsilylphenylthioacetal (18) by the sila-Pummerer rearrangement, although this was complicated by vinyl sulphide (20) formation in certain cases.Subsequent hydrolysis of (18) and (20) gave the ketone (3).
- Ager, David J.
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p. 195 - 204
(2007/10/02)
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