- Photoenolization/nucleophilic addition enables direct access to 3-alkyl-3-hydroxy-indolin-2-ones
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A light-driven, catalyst- and additive-free photoenolization/nucleophilic addition reaction for the synthesis of 3-benzyl-3-hydroxyindolin-2-ones is presented. In this reaction, 2-methylbenzophenones undergo light-induced enolization process to afford hydroxy-o-quinodimethanes (hydroxy-o-QDMs), which are then immediately captured by the electrophilic isatins. The reaction utilizes green and clean light energy to realize the C–H activation of the inert benzyl position of 2-methylbenzophenones. This method tolerates a wide scope of substrates and provides concise access to a series of novel 3-benzyl-3-hydroxyindolin-2-ones with 60–99% yields.
- Wang, Zhi-Lv,Tang, Li,Zeng, Wei-Mei,He, Yan-Hong,Guan, Zhi
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- Palladium-phosphinous acid-catalyzed cross-coupling of aryl and acyl halides with aryl-, alkyl-, and vinylzinc reagents
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(Chemical Equation Presented) Several palladium-phosphinous acids have been prepared and employed in cross-coupling reactions of aryl or acyl halides with aliphatic and aromatic organozinc reagents. The POPd7-catalyzed reaction of aryl halides, including electron-rich aryl chlorides, and arylzinc reagents was found to afford biaryls exhibiting alkoxy, alkylthio, amino, ketone, cyano, nitro, ester, and heteroaryl groups in 75-93% yield. Excellent results were obtained with sterically hindered substrates which gave di- and tri-ortho-substituted biaryls in up to 92% yield. Aryl halides also undergo POPd7-catalyzed aryl-vinyl and aryl-alkyl bond formation under mild conditions. Styrenes and alkylarenes were prepared in 79-93% yield from aryl halides and vinyl or alkylzinc reagents. The replacement of aryl halides by acyl halides provides access to ketones which were produced in up to 98% yield when POPd was used as catalyst. This approach overcomes the limited substrate scope, reduced regiocontrol, and low functional group tolerance of traditional Friedel-Crafts acylation methods.
- Xu, Hanhui,Ekoue-Kovi, Kekeli,Wolf, Christian
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p. 7638 - 7650
(2008/12/22)
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- Reaction of Diazonium Salts with Transition Metals. Part 13. Palladium-catalyzed Carbonylative Coupling of Arenediazonium Salts with Organotin Reagents to give Aromatic Ketones
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Palladium-catalyzed reactions of arenediazonium salts (ArN2X; Ar=Y-Ph, Y=H, 2-, 3-, 4-Me, 2-Ph, 2-, 3-MeO, 2-, 3-, 4-Cl, 4-Br, 4-I, 2-, 3-, and 4-NO2, X=BF4 and PF6) with carbon monoxide and organostannanes (R4Sn, R=Me, Et, and Ph; RSnMe3, R=Ph, 2-, 3-, 4-MeC6H4, and 4-ClC6H4; RSnEt3, R=4-NO2C6H4; RSnBu3, R=Ph) gave aromatic ketones (ArCOR) in good yields (40-95percent) at room temperature.
- Kikukawa, Kiyoshi,Idemoto, Tohru,Katayama, Atsuhiko,Kono, Kiyoshi,Wada, Fumio,Matsuda, Tsutomu
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p. 1511 - 1514
(2007/10/02)
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