- Se-Phenyl Areneselenosulfonates: Their Facile Formation and Striking Chemistry
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Benzeneseleninic acid reacts rapidly at 0 deg C with aromatic sulfinic acids according to the stoichiometry of eq 3 to form Se-phenyl arenesulfonates, PhSeSO2Ar (2), in high yield.In contrast to thiosulfonates, PhSSO2Ar, areneselenosulfonates are extremely photosensitive and undergo quite rapid photodecomposition.The principal products of this photodecomposition are the sulfonic anhydride, ArSO2OSO2Ar, and diphenyl diselenide.In the presence of added alkenes the facile photodissociation of 2 can be used to initiate a free-radical chain reaction that results in the addition of 2 to the alkene to form β-phenylseleno sulfones in good yield.The β-phenylseleno sulfones can be converted to synthetically useful α,β-unsaturated sulfones by oxidation of the β-phenylseleno group to the corresponding selenoxide and subsequent elimination of PhSeOH.Photoaddition of 2 to 2,5-norbornadiene to 5-(phenylseleno)-exo-3-nortricyclyl aryl sulfone as the almost exclusive product, while photoaddition to 1,5-cyclooctadiene gives a mixture of approximately equal amounts of the 1,2-adduct, 5-(phenylseleno)-6-arenesulfonyl-1-cyclooctene, and the product of transannular addition, 6-(phenylseleno)-exo-2-arenesulfonyl-cis-bicyclooctane.Besides their extraordinary ease of photodissociation, compounds 2 also react extremely readily with nucleophiles: Nu- + PhSeSO2Ar -> PhSeNu + ArSO2-.Kinetic studies show that the reactivity of PhSeSO2Ar with cyanide ion in such a reaction is 70000 times larger than the reactivity of the corresponding thiosulfonate, PhSSO2Ar.
- Gancarz, Roman A.,Kice, John L.
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p. 4899 - 4906
(2007/10/02)
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- Selenosulfonation: Boron Trifluoride Catalyzed or Thermal Addition of Selenosulfonates to Olefins. A Novel Regio- and Stereocontrolled Synthesis of Vinyl Sulfones.
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Se-Phenyl areneselenosulfonates 1 add to a variety of olefins to produce β-phenylseleno sulfones 2.The reaction may be performed in the presence of boron trifluoride etherate to produce chiefly or exclusively Markovnikov products arising from a stereospecific anti addition.Alternatively, the addition may be thermally induced to afford anti-Markovnikov products generated by a nonstereospecific free-radical process.The two modes of addition achieve complementary regiospecificity.The β-phenylseleno sulfones are converted in high yield to vinyl sulfones by stereospecific oxidation-elimination with m-chloroperbenzoic acid.
- Back, Thomas G.,Collins, Scott
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p. 3249 - 3256
(2007/10/02)
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- "Selenosulfonation": the addition of selenolsulfonates to olefins
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The reaction of phenyl areneselenolsulfonates with unhindered olefins affords β-phenylselenosulfone adducts, usually with high regio- and stereoselectivity.
- Back, Thomas G.,Collins, Scott
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p. 2215 - 2218
(2007/10/02)
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- PHOTODECOMPOSITION OF SELENOSULFONATES AND THEIR FACILE PHOTOADDITION TO ALKENES1
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Phenyl areneselenosulfonates (1) are very photosensitive and easily undergo photodecomposition via initial homolysis of the Se-S bond.In the presence alkenes this facile photodissociation of 1 can be used to initiate a free radical chain reaction (eq 6) that leads to addition of 1 to the alkene to form β-phenylselenosulfones (2).The photoaddition requires much shorter reaction times than the non-photolytic addition of 1 to alkenes described recently.
- Gancarz, Roman A.,Kice, John L.
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p. 4155 - 4158
(2007/10/02)
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