- One-Pot Sulfoxide Synthesis Exploiting a Sulfinyl-Dication Equivalent Generated from a DABSO/Trimethylsilyl Chloride Sequence
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A one-pot process for the synthesis of unsymmetrical sulfoxides using organometallic nucleophiles is described. Sulfur dioxide, delivered from the surrogate DABSO (DABCO-bis(sulfur dioxide)), acts as the initial electrophile and combines with the first organometallic reagent to generate a sulfinate intermediate. In situ conversion of the sulfinate to a sulfinate silyl ester, using TMS-Cl (trimethylsilyl chloride), generates a second electrophile, allowing addition of a second organometallic reagent. Organolithium or Grignard reagents can be employed, delivering sulfoxides in good to excellent yields.
- Lenstra, Danny C.,Vedovato, Vincent,Ferrer Flegeau, Emmanuel,Maydom, Jonathan,Willis, Michael C.
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supporting information
p. 2086 - 2089
(2016/06/01)
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- Tert-Butyl Sulfoxides: Key Precursors for Palladium-Catalyzed Arylation of Sulfenate Salts
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The present report describes an efficient and clean generation of sulfenate salts (R1SO-) by pyrolysis of readily available tert-butyl sulfoxides to give sulfenic acids (R1SOH) and traceless isobutene, followed by hydrogen abstraction with a weak inorganic base (K3PO4). The relevance of this process was exemplified through an in situ palladium-catalyzed cross-coupling reaction with aryl halides/triflates leading to aryl sulfoxides. The operationally simple C-S bond-forming protocol developed uses Pd(dba)2 as catalyst and Xantphos as ligand in toluene or a toluene/H2O mixture. Further extensions include the use of di-tert-butyl sulfoxide as an equivalent for sulfur monoxide dianion (SO2-) and the development of diastereoselective versions in the [2.2]paracyclophane and biaryl series.
- Gelat, Fabien,Lohier, Jean-Fran?ois,Gaumont, Annie-Claude,Perrio, Stéphane
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supporting information
p. 2011 - 2016
(2015/06/23)
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- Diastereoconvergent synthesis of trans -5-hydroxy-6-substituted-2- piperidinones by addition-cyclization-deprotection process
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A diastereoselective one-pot approach to access trans-5-hydroxy-6- substituted-2-piperidinones by an addition-cyclization-deprotection process has been developed, in which the stereogenic center at the C-6 position was solely controlled by α-OTBS group. The utility of this transformation is demonstrated by the asymmetric synthesis of the enantiomer of (-)-CP-99,994.
- Si, Chang-Mei,Huang, Wei,Du, Zhen-Ting,Wei, Bang-Guo,Lin, Guo-Qiang
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supporting information
p. 4328 - 4331
(2014/09/30)
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- Structural effects on the C-S bond cleavage in aryl tert -butyl sulfoxide radical cations
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The oxidation of a series of aryl tert-butyl sulfoxides (4-X-C 6H4SOC(CH3)3: 1, X = OCH 3; 2, X = CH3; 3, X = H; 4, X = Br) photosensitized by 3-cyano-N-methylquinolinium perchlorate (3-CN-NMQ+) has been investigated by steady-state irradiation and nanosecond laser flash photolysis (LFP) under nitrogen in MeCN. Products deriving from the C-S bond cleavage in the radical cations 1+?-4+? have been observed in the steady-state photolysis experiments. By laser irradiation, the formation of 3-CN-NMQ? (λmax = 390 nm) and 1 +?-4+? (λmax = 500-620 nm) was observed. A first-order decay of the sulfoxide radical cations, attributable to C-S bond cleavage, was observed with fragmentation rate constants (k f) that decrease by increasing the electron donating power of the arylsulfinyl substituent from 1.8 × 106 s-1 (4 +?) to 2.3 × 105 s-1 (1 +?). DFT calculations showed that a significant fraction of the charge is delocalized in the tert-butyl group of the radical cations, thus explaining the small substituent effect on the C-S bond cleavage rate constants. Via application of the Marcus equation to the kinetic data, a very large value for the reorganization energy (λ = 62 kcal mol-1) has been calculated for the C-S bond scission reaction in 1+?-4 +?.
- Cavattoni, Tullio,Del Giacco, Tiziana,Lanzalunga, Osvaldo,Mazzonna, Marco,Mencarelli, Paolo
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p. 4886 - 4894
(2013/07/11)
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- The synthesis of enantiomerically pure 4-substituted [2.2]paracyclophane derivatives by sulfoxide-metal exchange
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A general strategy for the synthesis of enantiomerically pure 4-substituted [2.2]paracyclophanes from a common sulfoxide precursor is described. The Royal Society of Chemistry 2005.
- Hitchcock, Peter B.,Rowlands, Gareth J.,Parmar, Rakesh
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p. 4219 - 4221
(2007/10/03)
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- Nucleophilic epoxidation of α′-hydroxy vinyl sulfoxides
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The nucleophilic epoxidation of a variety of α′-(1-hydroxyalkyl) vinyl sulfones and sulfoxides has been studied. The sulfones give rise to anti oxiranes with modest (E) or excellent (Z) selectivities and in good yields. The (E)-sulfoxides display low reactivity within a reinforcing/nonreinforcing scenario. The use of t-BuOOLi in Et2O allows for a highly syn-selective epoxidation-oxidation. The (Z)-sulfoxides display a remarkably high reactivity under these conditions. The reinforcing (S,Ss) diastereomers (3e-g) yield hydroxy sulfinyl oxiranes with high yields and selectivities. In contrast, the (R,Ss) diastereomers (4e-g) show diminished reactivities and a very substrate-dependent stereochemical outcome. The structure of these oxiranes has been secured by chemical correlations and an X-ray crystal structure.
- Fernandez de la Pradilla, Roberto,Fernandez, Jorge,Manzano, Pilar,Mendez, Paloma,Priego, Julian,Tortosa, Mariola,Viso, Alma,Martinez-Ripoll, Martin,Rodriguez, Ana
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p. 8166 - 8177
(2007/10/03)
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- Generation of oxiranyllithiums and oxiranyl Grignard reagents having a carbanion-destabilizing group from sulfinyloxiranes: Their property and an application to asymmetric synthesis of epoxides and alcohols
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The first generation of oxiranyllithiums and oxiranyl Grignard reagents having a carbanion-destabilizing group (alkyl group) was realized from sulfinyloxiranes via the ligand exchange reaction of sulfoxides with tert- butyllithium or ethylmagnesium chlori
- Satoh, Tsuyoshi,Kobayashi, Shigeko,Nakanishi, Shino,Horiguchi, Kyoko,Irisa, Shiro
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p. 2515 - 2528
(2007/10/03)
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- Titanium-Catalyzed, Asymmetric Sulfoxidation of Alkyl Aryl Sulfides with Optically Active Hydroperoxides
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The Ti-catalyzed, asymmetric oxidation of alkyl aryl sulfides by enantiomerically pure hydroperoxides (ee >99%) has been examined. Enantioselectivities with ee values up to ca. 80% were achieved for the oxygen transfer from (S)-(-)-1-phenylethyl hydroperoxide 2a to methyl phenyl and methyl p-tolyl sulfide 1a in CCl4 as solvent, but with much overoxidation to the corresponding sulfone 4. Detailed mechanistic studies showed that the enantioselectivity of the sulfide 1a oxidation results from a combination of a rather low (ee values >20%) asymmetric induction in the sulfoxidation and an effective kinetic resolution (ee values ca. 80% at 85% sulfide conversion) of the sulfoxide 3a by enantioselective oxidation to the sulfone 4a. The overoxidation (loss of chemoselectivity) is due to sulfoxide coordination to the Ti metal to generate a template in which the oxygen atom is intramolecularly transferred from the bound and activated, optically active hydroperoxide to the ligated sulfoxide in a stereocontrolled manner.
- Adam, Waldemar,Korb, Marion N.,Roschmann, Konrad J.,Saha-Moeller, Chantu R.
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p. 3423 - 3428
(2007/10/03)
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- Extremely Facile Ligand-Exchange and Disproportionation Reactions of Diaryl Sulfoxides, Selenoxides, and Triarylphosphine Oxides with Organolithium and Grignard Reagents
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Diaryl sulfoxides undergo unusually rapid ligand-exchange reaction upon treatment with organolithium reagents at -95 deg C.Optically pure phenyl p-tolyl sulfoxide (4b) reacted with organolithium reagents at the range from -20 to -95 deg C to give facile ligand-exchange and disproportionation products, i.e., diphenyl sulfoxide (7), recovered 4b, and di-p-tolyl sulfoxide (8) in a statistical ratio of 1:2:1 in quantitative yields, and the recovered 4b was completely racemized.This facile ligand exchange was observed in the similar reactions using only diaryl selenoxides and triarylphosphine oxides.The reactions of 18O-labeled phenyl p-tolyl sulfoxide (4c) with organolithium reagents gave products in a statistical ration without 18O scrambling, indicating that only the C-S bond cleavage took place under low temperature.It is suggested that the ligand exchange reactions occur by the nucleophilic attack by organolithium reagent at the sulfinyl sulfur atom, giving ?-sulfurane as an intermediate that collapses rapidly.These results suggest that the treatment of arylic sulfoxides, selenoxides, and phosphine oxides with strong bases should be effected with caution.
- Furukawa, Naomichi,Ogawa, Satoshi,Matsumura, Kazunori,Fujihara, Hisashi
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p. 6341 - 6348
(2007/10/02)
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- ORGANOSULPHUR COMPOUNDS-LXIX OPTICALLY ACTIVE SULPHINATES: A NEW TYPE OF ENANTIOSELECTIVE ASYMMETRIC SYNTHESIS AND KINETIC RESOLUTION
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Optically active sulphinates with the sulphur atom as a sole centre of chirality are prepared by two methods.The first involves the reaction of symmetrical sulphites with tert-butylmagnesium chloride in the presence of optically active aminoalcohols.This new asymmetric, enantioselective synthesis affords t-butylsulphinates with 40-70percent enantiomeric excess values.The second approach is based on a new type of kinetic resolution taking place when racemic sulphinates are reacted with tert-butylmagnesium chloride complexed by optically active alkaloid bases.Both the recovered sulphinates and sulphoxides formed in this reaction show moderate optical purities.
- Drabowicz, Jozef,Legedz, Slawomir,Mikolajczik, Marian
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p. 5243 - 5252
(2007/10/02)
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- Substitution at Tricoordinate Sulfur(IV). Rearrangement of Sulfinanilides to Anilino Sulfoxides
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Seven N-methyl-N-aryl-p-toluenesulfinamides (1, 3-Me2NC6H4; 2, 3-MeOC6H4; 3, 4-MeOC6H4; 4, 3-MeC6H4; 5, Ph; 6, 3-ClC6H4; 7, 3-FC6H4), N-(3-methoxyphenyl)-p-toluenesulfinamide (8), and two N-methyl-N-aryl-methanesulfinamides (9, 3-Me2NC6H4; 10, 3-MeOC6H4) were prepared from the corresponding sulfinyl chloride and the substituted aniline.Sulfinanilides 2 and 7 were treated with alkyllithiums in vain attempts to induce rearrangement to the diaryl sulfoxides via endocyclic nucleophilic attack by carbon 2 of the aniline ring on sulfur.Instead, the alkyllithium cleaved the S-N bond to yield the aniline and alkyl p-tolyl sulfoxide.Upon treatment with gaseous HCl in chloroform, the sulfinanilides rearranged as follows: 1 gave 4-(dimethylamino)-2-(methylamino)-4'-methyldiphenyl sulfoxide (92percent yield), 2 gave 2-methoxy-4-(methylamino)-4'-methyldiphenyl sulfoxide (26percent yield) and 4-methoxy-2-(methylamino)-4'-methyldiphenyl sulfoxide (70percent yield), 4 gave 2-methyl-4-(methylamino)-4'-methyldiphenyl sulfoxide (71percent yield), 9 gave methyl 4-(dimethylamino)-2-(methylamino)phenylsulfoxide (20percent yield), and 10 gave methyl 2-methoxy-4-(methylamino)phenyl sulfoxide (5percent yield).Sulfinanilides 3 and 5-8 did not rearrange.A tentative mechanism for the rearrangement is proposed.
- Andersen, Kenneth K.,Malver, Olaf
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p. 4803 - 4807
(2007/10/02)
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- Chemistry of Oxaziridines. 3. Asymmetric Oxidation of Organosulfur Compounds Using Chiral 2-Sulfonyloxaziridines
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Chiral 2-sulfonyloxaziridines, 9-12, afford the best enantioselectivity of any chiral oxidizing reagent for the asymmetric oxidation of sulfides and disulfides to sulfoxides and thiosulfinates, respectively, 5-8 times better than chiral peracids.For asymmetric oxidations using 9-12, the configuration of the oxaziridine three-membered ring was shown to control the configuration of the product, which could be predicted using a chiral recognition mechanism (Figure 2).The increased asymmetric bias exhibited by chiral 2-sulfonyloxaziridines was attrbuted to the fact that the active-site oxygen was incorporated into a rigid chiral environment.The group size difference (GSD) effect in both the oxaziridine and substrate play important roles in determining the absolute configuration of the product and the magnitude of the asymmetric bias.As the GSD increases the enantioselectivity increases.
- Davis, Franklin A.,Jenkins, Robert H.,Awad, Sami B.,Stringer, Orum D.,Watson, William H.,Galloy, Jean
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p. 5412 - 5418
(2007/10/02)
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