Search results
Search for "sultine" in Full Text gives 3 result(s) in Beilstein Journal of Organic Chemistry.
CF3-substituted carbocations: underexploited intermediates with great potential in modern synthetic chemistry
- Anthony J. Fernandes,
- Armen Panossian,
- Bastien Michelet,
- Agnès Martin-Mingot,
- Frédéric R. Leroux and
- Sébastien Thibaudeau
Beilstein J. Org. Chem. 2021, 17, 343–378, doi:10.3762/bjoc.17.32
- carbenium ions have also been suggested to exist as reaction intermediates. During their investigations on the reactivity of sulfuranes under acidic conditions, Martin et al. reported that sulfurane 44 reacts with triflic acid to provide alcohol 9g and sultine 46, according to 1H and 19F NMR assignments
- , and triflate 45f, which was isolated after basic workup of the reaction (59% yield) [63]. Hence, protonation of 44 led to dialkoxysulfonium triflate 47 along with the release of alcohol 9g. The subsequent formation of the excellent sultine leaving group 46 (assumed to be as good of a leaving group as
Graphical Abstract
Figure 1: Stabilizing interaction in the CF3CH2+ carbenium ion (top) and structure of the first observable fl...
Scheme 1: Isodesmic equations accounting for the destabilizing effect of the CF3 group. ΔE in kcal⋅mol−1, cal...
Scheme 2: Stabilizing effect of fluorine atoms by resonance electron donation in carbenium ions (δ in ppm).
Scheme 3: Direct in situ NMR observation of α-(trifluoromethyl)carbenium ion or protonated alcohols. Δδ = δ19...
Scheme 4: Reported 13C NMR chemical shifts for the α-(trifluoromethyl)carbenium ion 10c (δ in ppm).
Scheme 5: Direct NMR observation of α-(trifluoromethyl)carbenium ions in situ (δ in ppm).
Scheme 6: Illustration of the ion pair solvolysis mechanism for sulfonate 13f. YOH = solvent.
Figure 2: Solvolysis rate for 13a–i and 17.
Figure 3: Structures of allyl triflates 18 and 19 and allyl brosylate 20. Bs = p-BrC6H4SO2.
Figure 4: Structure of tosylate derivatives 21.
Figure 5: a) Structure of triflate derivatives 22. b) Stereochemistry outcomes of the reaction starting from (...
Scheme 7: Solvolysis reaction of naphthalene and anthracenyl derivatives 26 and 29.
Figure 6: Structure of bisarylated derivatives 34.
Figure 7: Structure of bisarylated derivatives 36.
Scheme 8: Reactivity of 9c in the presence of a Brønsted acid.
Scheme 9: Cationic electrocyclization of 38a–c under strongly acidic conditions.
Scheme 10: Brønsted acid-catalyzed synthesis of indenes 42 and indanes 43.
Scheme 11: Reactivity of sulfurane 44 in triflic acid.
Scheme 12: Solvolysis of triflate 45f in alcoholic solvents.
Scheme 13: Synthesis of labeled 18O-52.
Scheme 14: Reactivity of sulfurane 53 in triflic acid.
Figure 8: Structure of tosylates 56 and 21f.
Scheme 15: Resonance forms in benzylic carbenium ions.
Figure 9: Structure of pyrrole derivatives 58 and 59.
Scheme 16: Resonance structure 60↔60’.
Scheme 17: Ga(OTf)3-catalyzed synthesis of 3,3’- and 3,6’-bis(indolyl)methane from trifluoromethylated 3-indol...
Scheme 18: Proposed reaction mechanism.
Scheme 19: Metal-free 1,2-phosphorylation of 3-indolylmethanols.
Scheme 20: Superacid-mediated arylation of thiophene derivatives.
Scheme 21: In situ mechanistic NMR investigations.
Scheme 22: Proposed mechanisms for the prenyltransferase-catalyzed condensation.
Scheme 23: Influence of a CF3 group on the allylic SN1- and SN2-mechanism-based reactions.
Scheme 24: Influence of the CF3 group on the condensation reaction.
Scheme 25: Solvolysis of 90 in TFE.
Scheme 26: Solvolysis of allyl triflates 94 and 97 and isomerization attempt of 96.
Scheme 27: Proposed mechanism for the formation of 95.
Scheme 28: Formation of α-(trifluoromethyl)allylcarbenium ion 100 in a superacid.
Scheme 29: Lewis acid activation of CF3-substituted allylic alcohols.
Scheme 30: Bimetallic-cluster-stabilized α-(trifluoromethyl)carbenium ions.
Scheme 31: Reactivity of cluster-stabilized α-(trifluoromethyl)carbenium ions.
Scheme 32: α-(Trifluoromethyl)propargylium ion 122↔122’ generated from silyl ether 120 in a superacid.
Scheme 33: Formation of α-(trifluoromethyl)propargylium ions from CF3-substituted propargyl alcohols.
Scheme 34: Direct NMR observation of the protonation of some trifluoromethyl ketones in situ and the correspon...
Scheme 35: Selected resonance forms in protonated fluoroketone derivatives.
Scheme 36: Acid-catalyzed Friedel–Crafts reactions of trifluoromethyl ketones 143a,b and 147a–c.
Scheme 37: Enantioselective hydroarylation of CF3-substituted ketones.
Scheme 38: Acid-catalyzed arylation of ketones 152a–c.
Scheme 39: Reactivity of 156 in a superacid.
Scheme 40: Reactivity of α-CF3-substituted heteroaromatic ketones and alcohols as well as 1,3-diketones.
Scheme 41: Reactivity of 168 with benzene in the presence of a Lewis or Brønsted acid.
Scheme 42: Acid-catalyzed three-component asymmetric reaction.
Scheme 43: Anodic oxidation of amines 178a–c and proposed mechanism.
Scheme 44: Reactivity of 179b in the presence of a strong Lewis acid.
Scheme 45: Trifluoromethylated derivatives as precursors of trifluoromethylated iminium ions.
Scheme 46: Mannich reaction with trifluoromethylated hemiaminal 189.
Scheme 47: Suitable nucleophiles reacting with 192 after Lewis acid activation.
Scheme 48: Strecker reaction involving the trifluoromethylated iminium ion 187.
Scheme 49: Reactivity of 199 toward nucleophiles.
Scheme 50: Reactivity of 204a with benzene in the presence of a Lewis acid.
Scheme 51: Reactivity of α-(trifluoromethyl)-α-chloro sulfides in the presence of strong Lewis acids.
Scheme 52: Anodic oxidation of sulfides 213a–h and Pummerer rearrangement.
Scheme 53: Mechanism for the electrochemical oxidation of the sulfide 213a.
Scheme 54: Reactivity of (trifluoromethyl)diazomethane (217a) in HSO3F.
Figure 10: a) Structure of diazoalkanes 217a–c and b) rate-limiting steps of their decomposition.
Scheme 55: Deamination reaction of racemic 221 and enantioenriched (S)-221.
Scheme 56: Deamination reaction of labeled 221-d2. Elimination products were formed in this reaction, the yiel...
Scheme 57: Deamination reaction of 225-d2. Elimination products were also formed in this reaction in undetermi...
Scheme 58: Formation of 229 from 228 via 1,2-H-shift.
Scheme 59: Deamination reaction of 230. Elimination products were formed in this reaction, the yield of which ...
Scheme 60: Deamination of several diazonium ions. Elimination products were formed in these reactions, the yie...
Scheme 61: Solvolysis reaction mechanism of alkyl tosylates.
Scheme 62: Solvolysis outcome for the tosylates 248 and 249 in HSO3FSbF5.
Figure 11: Solvolysis rate of 248, 249, 252, and 253 in 91% H2SO4.
Scheme 63: Illustration of the reaction pathways. TsCl, pyridine, −5 °C (A); 98% H2SO4, 30 °C (B); 98% H2SO4, ...
Scheme 64: Proposed solvolysis mechanism for the aliphatic tosylate 248.
Scheme 65: Solvolysis of the derivatives 259 and 260.
Scheme 66: Solvolysis of triflate 261. SOH = solvent.
Scheme 67: Intramolecular Friedel–Crafts alkylations upon the solvolysis of triflates 264 and 267.
Scheme 68: α-CF3-enhanced γ-silyl elimination of cyclobutyltosylates 270a,b.
Scheme 69: γ-Silyl elimination in the synthesis of a large variety of CF3-substituted cyclopropanes. Pf = pent...
Scheme 70: Synthetic pathways to 281. aNMR yields.
Scheme 71: The cyclopropyl-substituted homoallylcyclobutylcarbenium ion manifold.
Scheme 72: Reactivity of CF3-substituted cyclopropylcarbinyl derivatives 287a–c. LG = leaving group.
Scheme 73: Reactivity of CF3-substituted cyclopropylcarbinyl derivatives 291a–c.
Scheme 74: Superacid-promoted dimerization or TFP.
Scheme 75: Reactivity of TFP in a superacid.
Scheme 76: gem-Difluorination of α-fluoroalkyl styrenes via the formation of a “hidden” α-RF-substituted carbe...
Scheme 77: Solvolysis of CF3-substituted pentyne 307.
Scheme 78: Photochemical rearrangement of 313.
Figure 12: Structure of 2-norbornylcarbenium ion 318 and argued model for the stabilization of this cation.
Figure 13: Structures and solvolysis rate (TFE, 25 °C) of the sulfonates 319–321. Mos = p-MeOC6H4SO2.
Scheme 79: Mechanism for the solvolysis of 323. SOH = solvent.
Scheme 80: Products formed by the hydrolysis of 328.
Scheme 81: Proposed carbenium ion intermediates in an equilibrium during the solvolysis of tosylates 328, 333,...
Diversity-oriented synthesis of spirothiazolidinediones and their biological evaluation
- Sambasivarao Kotha,
- Gaddamedi Sreevani,
- Lilya U. Dzhemileva,
- Milyausha M. Yunusbaeva,
- Usein M. Dzhemilev and
- Vladimir A. D’yakonov
Beilstein J. Org. Chem. 2019, 15, 2774–2781, doi:10.3762/bjoc.15.269
- spirothiazolidinedione derivatives (Scheme 4). Further, the dibromo N-methyl derivative of thiazolidinedione 8b was converted to sultine 13 using rongalite and tetra-n-butylammonium bromide (TBAB) in DMF. Then, sultine 13 was treated with different dienophiles 14 in a DA fashion and linearly fused spirocyclic
- derivatives. [2 + 2 + 2] Cyclotrimerization of N-methylthiazolidinedione. Unexpected product 5b obtained in the attempted NH-protection of thiazolidinedione with (Boc)2O. [2 + 2 + 2] Cyclotrimerization of dipropargylthiazolidinediones with propargyl halides. Formation of sultine 13 from compound 8b followed
Graphical Abstract
Scheme 1: Conventional method of synthesis of thiazolidine-2,4-dione derivatives.
Scheme 2: [2 + 2 + 2] Cyclotrimerization of N-methylthiazolidinedione.
Scheme 3: Unexpected product 5b obtained in the attempted NH-protection of thiazolidinedione with (Boc)2O.
Figure 1: Comparison of 13C NMR values of 9 and 5b.
Scheme 4: [2 + 2 + 2] Cyclotrimerization of dipropargylthiazolidinediones with propargyl halides.
Scheme 5: Formation of sultine 13 from compound 8b followed by DA reaction.
Scheme 6: Dipropargylation of 2,4-thiazolidinedione derivatives.
Scheme 7: [2 + 2 + 2] Cycloaddition in the presence of Wilkinson’s catalyst.
Scheme 8: N-Ester derivative 18 hydrolysis to N-acid derivative 22.
Scheme 9: Synthesis of triazolo derivative 24 via click reaction.
Thermodynamically stable [4 + 2] cycloadducts of lanthanum-encapsulated endohedral metallofullerenes
- Yuta Takano,
- Yuki Nagashima,
- M. Ángeles Herranz,
- Nazario Martín and
- Takeshi Akasaka
Beilstein J. Org. Chem. 2014, 10, 714–721, doi:10.3762/bjoc.10.65
- in situ from the sultine 4,5-benzo-3,6-dihydro-1,2-oxathiin 2-oxide and its derivative, to La metal-encapsulated fullerenes, La2@C80 or La@C82, afforded the novel derivatives of endohedral metallofullerenes (3a,b, 4a,b and 5b). Molecular structures of the resulting compounds were elucidated using
- metallofullerene derivatives for the use in material science. Keywords: carbon nanomaterials; dynamic NMR; endofullerenes; La2@C80; La@C82; sultine; Introduction Endohedral metallofullerenes (EMFs) are a family of nanocarbons, which encapsulated one or more metal atoms inside a hollow carbon cage [1][2][3][4
- precursors to afford [4 + 2] cycloadducts of fullerenes, the sultine 4,5-benzo-3,6-dihydro-1,2-oxathiin 2-oxide and its derivatives are useful to afford thermodynamically stable compounds because thermolysis of sultine affords highly reactive o-quinodimethanes by extrusion of sulfur dioxide without
Graphical Abstract
Scheme 1: Synthesis of [4 + 2] adducts of La2@C80.
Figure 1: HPLC profiles of the reaction solutions (black) before and (red) after the reaction of La2@C80 and ...
Figure 2: MALDI–TOF mass (negative mode) spectra of (a) 3b and (b) 4b, using 1,1,4,4-tetraphenyl-1,3-butadien...
Figure 3: UV–vis/near-IR absorption spectra of 3b and 4b recorded by the diode array detector of the HPLC app...
Figure 4: MALDI–TOF mass spectrum (negative mode) of the reaction mixture from La2@C80 and 1a, using 1,1,4,4-...
Figure 5: 1H NMR spectra of (a) the mixture of 3a and 4a in C2D2Cl4 at 248 K, and (b) isolated 4a at 230 K, r...
Figure 6: HPLC profiles of the mixture of 3a and 4a, (a) after heating in refluxing 1,2-dichlorobenzene and (...
Figure 7: HPLC profiles of the reaction mixture of 3b and 4b, (black) before and (red) after heating in reflu...
Figure 8: UV–vis/near-IR absorption spectra of 3b and 4a in toluene.
Figure 9: Temperature-dependent 1H NMR spectra of 4a in C2D2Cl4 (left) at 300 MHz, and (right) at 500 MHz for...
Scheme 2: Synthesis of [4 + 2] adducts of La@C82.
Figure 10: HPLC profiles of the reaction mixture for 5b. Conditions: column, Buckyprep (Ø 4.6 mm × 250 mm); el...
Figure 11: MALDI–TOF mass spectra (negative mode) of 5b, using 1,1,4,4-tetraphenyl-1,3-butadiene as matrix.
Figure 12: Vis–near-IR spectra of 5b, 6 and La@C82 in CS2.
Figure 13: 1H NMR spectrum of [5b]− in acetone-d6/CS2 (3/1 = v/v) at 223 K.
Figure 14: 13C NMR spectrum of [5b]− in acetone-d6/CS2 (3/1 = v/v).
Figure 15: HPLC profiles for comparison of the thermal stabilities of (a) 5b and (b) 6 at 30 °C. Conditions: c...
