- Dual role of acetanilides: Traceless removal of a directing group through deacetylation/diazotation and palladium-catalyzed C-C-coupling reactions
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The acetamide group enables regioselective oxidative ortho-C-H activation reactions, such as Pd-catalyzed acylation. The synthetic utility of these transformations can be significantly enhanced by using the acetamide as a quasi-leaving group in a subsequent conventional Pd-catalyzed coupling or cross-coupling reaction. The concept is illustrated herein for the synthesis of o-alkenyl- and o-arylphenones, which have potential for the synthesis of arylated aromatic heterocycles.
- Schmidt, Bernd,Elizarov, Nelli,Schilde, Uwe,Kelling, Alexandra
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- Multibond Forming Tandem Reactions of Anilines via Stable Aryl Diazonium Salts: One-Pot Synthesis of 3,4-Dihydroquinolin-2-ones
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A fast and effective one-pot tandem process that generates Heck coupled products from readily available anilines via stable aryl diazonium tosylate salts was developed. The mild and simple procedure involves rapid formation of aryl diazonium salts using a polymer-supported nitrite reagent and p-tosic acid, followed by a base-free Heck-Matsuda coupling with acrylates and styrenes. Using 2-nitroanilines as substrates, the one-pot tandem process was extended for the direct synthesis of 3,4-dihydroquinolin-2-ones. In this case, following diazotization and Heck-Matsuda coupling to give methyl cinnamates, addition of hydrogen and reutilization of the palladium catalyst for reduction of the nitro group and hydrogenation of the alkene resulted in efficient formation of 3,4-dihydroquinolin-2-ones. The synthetic utility of this one-pot, four-stage process was demonstrated with the five-pot synthesis of a quinolinone-based sodium ion channel modulator.
- Faggyas, Réka J.,Grace, Megan,Williams, Lewis,Sutherland, Andrew
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p. 12595 - 12608
(2018/10/15)
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- Heck-type reaction of aryldiazonium silica sulfates
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Aryldiazonium silica sulfates were employed as new and efficient reagents for Heck-type arylation reactions with styrene and methyl acrylate. The reactions were carried out in an organic solvent, in the presence of Pd(OAc)2 as precatalyst without use of base and free ligand. The trans isomers of desired products, methyl cinnamates and stilbenes, were obtained with full conversion. Use of a catalytic amount of Pd(OAc)2 produced the corresponding products in short reaction times and excellent yields. Springer-Verlag 2011.
- Pirisedigh, Azadeh,Zarei, Amin,Seyedjamali, Hojjat,Khazdooz, Leila,Hajipour, Abdol R.
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experimental part
p. 791 - 795
(2012/09/05)
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