- Bidentate oxazoline-imine ruthenium(II) complexes: Intermediates in the methanolysis/hydration of nitrile groups
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The reaction of [RuCl2(p-cymene)]2 with benzoxazoleacetonitriles and NH4+BF4 - in methanol leads to bidentate N,N′-benzoxazole-methoxyimine- ruthenium(II) complexes 7, corresponding to the addition of methanol to the ruthenium(II)-activated nitrile triple bond. The X-ray structure of a complex 7 shows equivalent Ru-N and slightly different C=N bond distances. The catalytic hydration of benzoxazolacetonitriles with [RuCl2(p-cymene)] 2 in methanol/water leads to quantitative formation of corresponding amides under mild conditions.
- Ben Ammar, Hamed,Miao, Xiaowei,Fischmeister, Cedric,Toupet, Loic,Dixneuf, Pierre H.
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- Regio- and diastereoselective decarboxylative coupling of heteroaromatic alkanes
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Allylic esters of heteroaromatic alkanes undergo facile palladium-catalyzed decarboxylative coupling. The resulting C-C bond is formed with high diastereoselectivity and high regioselectivity for coupling at the more substituted allyl terminus. It is proposed that this unusual combination of selectivities results from a tandem allylation/aza-Cope rearrangement sequence. After allylation, decarboxylative dearomatization produces an intermediate for the aza-Cope rearrangement. The subsequent aza-Cope rearrangement occurs under mild conditions because it is driven by rearomatization. Copyright
- Waetzig, Shelli R.,Tunge, Jon A.
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p. 4138 - 4139
(2008/01/27)
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- Catalytic asymmetric cyclopropanation of heteroaryldiazoacetates
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Rh2(S-DOSP)4-catalyzed decomposition of heteroaryldiazoacetates in the presence of styrene results in highly diastereoselective and enantioselective cyclopropanations. Heteroaryldiazoacetates containing both electron-rich and electron-deficient heterocycles, such as thiophene, furan, pyridine, indole, oxazole, isoxazole, and benzoxazole, are effective in this chemistry. These studies broaden the range of diazo compounds containing both electron-withdrawing and electron-donating groups, which undergo highly diastereoselective cyclopropanations.
- Davies,Townsend
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p. 6595 - 6603
(2007/10/03)
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- METHYL DIALKYLAMINOPROPIOLATES IN REACTIONS WITH BIFUNCTIONAL COMPOUNDS
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Methyl dialkylaminopropiolates react with bifunctional reagents with the formation of heterocyclic compounds, and the direction of the reaction is determined by the type of bifunctional group. 1,2-Diamines (ethylenediamine, o-phenylenediamine) add at both reaction centers of the substrate, forming seven-membered heterocycles of the diazepinone and benzodiazepinone series. o-Aminophenol and o-aminothiophenol react exclusively at the ynamine fragment, and 2-substituted benzoxazole and benzothiazole are produced as a result of cyclization.
- Ostroumov, I. G.,Tsil'ko, A. E.,Maretina, I. A.
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p. 2092 - 2095
(2007/10/02)
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