- Mechanistic organic chemistry in a microreactor. Zeolite-controlled photooxidations of organic sulfides
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The intrazeolite and solution photooxygenations of a series of sulfides have been compared. The unusual zeolite environment enhances the rates of reaction, it suppresses the Pummerer rearrangements, and it has a dramatic effect on the sulfoxide/sulfone ratio. A detailed kinetic study utilizing trapping experiments and intramolecular competition provides evidence for cation complexation to a persulfoxide intermediate as the underlying phenomenon for the unique intrazeolite behavior. For example, the enhanced rate of reaction is traced to the cation stabilization of the persulfoxide toward unproductive decomposition to substrate and triplet oxygen.
- Clennan, Edward L.,Zhou, Wenhui,Chan, Jacqueline
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p. 9368 - 9378
(2007/10/03)
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- Grignard Addition Reactions to 1,4-Difunctionalized But-2-ynes
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Trisubstituted alkenes of E geometry have been prepared by anti addition of Grignard reagents to 1,4-difunctionalized but-2-ynes.Addition of primary, secondary and aromatic Grignard reagents to but-2-yne-1,4-diol provided (E)-2-substituted but-2-ene-1,4-diols as major products along with the corresponding 2-substituted buta-2,3-dien-1-ols.Addition of phenylmagnesium bromide to the mono- and di-methyl ethers of but-2-yne-1,4-diol gave 2,3-diphenyl-1,3-diene.Treatment of 4-dimethylaminobut-2-yn-1-ol with primary alkyl and alkenyl Grignard reagents afforded the 2-substituted anti addition product regiospecifically, stereospecifically and in high yield.Reaction of 1-dimethylamino-4-methoxybut-2-yne with butylmagnesium bromide provided only the 3-substituted anti addition product in good yield.
- Silva, Anthony N. De,Francis, Craig L.,Ward, A. David
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p. 1657 - 1672
(2007/10/02)
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- Effect of 3- and 4-Methyl Substituents on the Photocyclization of N-(3-Alkenyl)phthalimides: Synthesis of Pyrroloisoindoles and Pyridoisoindoles
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Photolysis of N-(3-alkenyl)phthalimides 2 in methanol gave tetrahydro-5H-pyrroloisoindol-5-ones 3 and/or tetrahydropyridoisoindol-6(2H)-ones 4 depending on the degree of substitution at the olefin carbons of 2.Electron transfer followed by the anti-Markownikoff addition of methanol is proposed as a possible pathway.Keywords - N-(3-alkenyl)phthalimide; photocyclization; pyrroloisoindole; pyridoisoindole; electron transfer; anti-Markownikoff addition
- Machida, Minoru,Oda, Kazuaki,Kanaoka, Yuichi
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