- Isomerisation of Vinyl Sulfones for the Stereoselective Synthesis of Vinyl Azides
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Reported is the construction, and facile base-mediated conversation of ten differently substituted 3-azido E-vinyl sulfones (γ-azido-α,β-unsaturated sulfones) into their isomeric vinyl azide counterparts. The requisite 3-azido E-vinyl sulfones were prepared from 3-bromo E-vinyl sulfones, which in turn were accessed from allyl sulfones via a bromination-elimination sequence. In relation to this a one-pot azidation-isomerisation sequence was developed which enabled the direct formation of the vinyl azides from the corresponding 3-bromo E-vinyl sulfones. Similarly, a convenient one-pot Horner–Wadsworth–Emmons olefination-isomerisation approach was utilised in order to prepare some of the allylic sulfones used in this study. The vinyl azide forming process typically proceeded with high levels of Z-selectivity, although this was dependent on the vinyl sulfone substitution pattern. Thus, with either no substituent or a methyl group in the γ- or β-position, relative to the sulfone, good, to high levels of Z-selectivity (Z/E = 85:15 to ≥ 95:5) were obtained. However, incorporation of an α-sulfonyl methyl substituent led to an E-selective process (Z/E = 20:80). A non-bonding interaction between the azido group and the α-sulfonyl vinylic proton is proposed, which acts as a conformational control mechanism to help guide the stereochemical outcome.
- Collins, Niall,Connon, Robert,Evans, Paul,Sánchez-Sanz, Goar
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supporting information
p. 6228 - 6235
(2020/10/02)
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- Stereoselective Synthesis of Z-α,β-Unsaturated Sulfones Using Peterson Reagents
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New Peterson reagents were prepared by introducing alkyloxy groups on the silicon atom in order to fix the conformation of the sulfone anion. The reagents 1d and 1e reacted with a variety of aldehydes after the treatment with Li-base to give Z-α,β-unsaturated sulfones with up to >99:1 selectivity in good to excellent yields. For the reaction with aliphatic aldehydes, CPME (cyclopentyl methyl ether) is the choice of solvent, while DME (1,2-dimethoxyethane) gave higher selectivity for the reaction with aromatic aldehydes.
- Ando, Kaori,Wada, Tomohiro,Okumura, Miho,Sumida, Hiroshi
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supporting information
p. 6026 - 6029
(2016/01/09)
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- Radical-mediated thiodesulfonylation of the vinyl sulfones: access to (α-fluoro)vinyl sulfides
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Radical-mediated thiodesulfonylation of the vinyl and (α-fluoro)vinyl sulfones, derived from aldehydes and ketones, with aryl thiols in organic or aqueous medium provided access to vinyl and (α-fluoro)vinyl sulfides. The vinyl sulfides were formed predominantly with E stereochemistry independent of the stereochemistry of the starting vinyl sulfones.
- Sacasa, Pablo R.,Zayas, Jessica,Wnuk, Stanislaw F.
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scheme or table
p. 5424 - 5427
(2009/12/06)
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- Preparation and reaction of phenylsulfonyl-substituted dizinciomethane
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Treatment of dibromomethyl phenyl sulfone with zinc powder in the presence of a catalytic amount of lead in THF afforded phenylsulfonyl-substituted dizinciomethane. The species converts a ketone or aldehyde into an alkenyl sulfone via a Wittig-type olefination reaction with the assistance of β-TiCl3. Copyright
- Baba, Yoko,Toshimitsu, Akio,Matsubara, Seijiro
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p. 864 - 865
(2008/02/12)
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- Asymmetric synthesis of anti-1,2-amino alcohols via the borono-Mannich reaction: A formal synthesis of (-)-swainsonine
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Chiral α-hydroxy aldehydes generated in situ by the ADH reaction of vinyl sulfones undergo a borono-Mannich reaction with β-styrenyl boronic acid and primary amines to give anti-1,2-amino alcohols in high enantiomeric purities (83-95% ee). This new method allows much more rapid access to these valuable chiral building blocks that has been used in a short formal synthesis (10 synthetic steps from 4-penten-1-ol) of (-)-swainsonine.
- Au, Christopher W. G.,Pyne, Stephen G.
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p. 7097 - 7099
(2007/10/03)
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- Radical-mediated silyl- and germyldesulfonylation of vinyl and (α-fluoro)vinyl sulfones: Application of tris(trimethylsilyl)silanes and tris(trimethylsilyl)germanes in Pd-catalyzed couplings
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Equation presented. Radical-mediated silyl- and germyldesulfonylations of various vinyl and (α-fluoro)vinyl sulfones with tris(trimethylsilyl)silane and germanium hydrides provide access to vinyl and (α-fluoro)vinyl silanes and germanes. Upon oxidative treatment with hydrogen peroxide in basic aqueous solution, the vinyl tris(trimethylsilyl)silanes and -germanes undergo Pd-catalyzed cross-couplings with aryl halides.
- Wnuk, Stanislaw F.,Garcia Jr., Pedro I.,Wang, Zhizhong
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p. 2047 - 2049
(2007/10/03)
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- Decarboxylative radical addition to vinylsulphones and vinylphosphonium bromide: Some further novel transformations of geminal (pyridine-2-thiyl) phenylsulphones
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Irradiation of O-acyl derivatives 1 of N-hydroxy-2-thiopyridone with visible light in the presence of phenyl vinyl sulphone or vinyl triphenylphosphonium bromide leads to the corresponding adducts 8 and 9 which can undergo a wide variety of further transformations.
- Barton,Boivin,Crepon nee da Silva,Sarma,Togo,Zard
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p. 7091 - 7108
(2007/10/02)
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- SOME FURTHER NOVEL TRANSFORMATIONS OF GEMINAL (PYRIDINE-2-THIYL) PHENYLSULPHONES
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Geminal (pyridine-2-thiyl) phenylsulphones, obtained by decarboxylative radical addition of O-acyl derivatives of N-hydroxy-2-thiopyridone onto phenyl vinyl sulphone, undergo a wide variety of further transformations when subjected to sodium telluride or to organoaluminum reagents.
- Barton, Derek H. R.,Boivin, Jean,Sarma, Jadab,Silva, Elisabeth da,Zard, Samir Z.
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p. 4237 - 4240
(2007/10/02)
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