- Synthesis of racemic and enantiomerically enriched α- oxyfunctionalized benzocyclanones and chromanones by dimethyldioxirane and dimethyldioxirane/Mn(III) salen system
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Enolacetates of benzocyclanones and chromanones were synthesized and treated with dimethyldioxirane and the asymmetric oxidizing system dimethyldioxirane/chiral, non-racemic Mn(III) salen complex/axial ligand. The latter reagent resulted in the corresponding enantiomerically enriched cyclic α-hydroxy ketones and their acetates in moderate-to-good yields and modest enantioselectivity under mild and neutral conditions from tetralone and chromanone. On the contrary, flavanone provided poor yields due to the competitive C-H insertion at position 2. The use of R,R-Mn(III)salen catalyst induced an S absolute configuration at the position α in the whole series. Springer-Verlag 2004.
- Patonay, Tamas,Jeko, Jozsef,Kiss-Szikszai, Attila,Levai, Albert
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p. 743 - 756
(2007/10/03)
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- Synthesis of α-hydroxy ketones using a HOF·MeCN complex
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The complex, HOF·MeCN made directly by bubbling fluorine through aqueous acetonitrile, reacts quickly and efficiently with enolic forms of ketones to produce α-hydroxy ketones.
- Rozen, Shlomo,Bareket, Yifat
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p. 627 - 628
(2007/10/03)
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- Photolysis of cyclic enol esters in the presence or absence of a single electron transfer photosensitizer
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The photochemistry of enol esters 1 is dominated by electrocyclic ring opening (1b → 3+4), 1,3-acyl migration (1c,d → 6c,d) and [2 + 2] dimerization (1d → 11). Photosensitization with triphenylpyrylium tetrafluoroborate (TPT) enhances formation of oxidation products (1b → 5,1c,d → 9c,d + 10c,d), presumably through the intermediacy of radical cations 1b-d+.
- Climent,Garcia,Iborra,Miranda,Primo
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p. 9289 - 9296
(2007/10/02)
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