Facile and innovative catalytic protocol for intramolecular Friedel–Crafts cyclization of Morita–Baylis–Hillman adducts: Synergistic combination of chiral (salen)chromium(III)/BF₃·OEt₂ catalysis

• Karthikeyan Soundararajan,
• Helen Ratna Monica Jeyarajan,
• Raju Subimol Kamarajapurathu and
• Karthik Krishna Kumar Ayyanoth

Beilstein J. Org. Chem. 2021, 17, 2186–2193, doi:10.3762/bjoc.17.140

• -deficient arenes [4][5][6][7]. Operating FC reactions in versatile synthons such as Morita–Baylis–Hillman (MBH) adducts is a challenging process. Inter/intramolecular Friedel–Crafts reactions of Morita–Baylis–Hillman adducts leads to a variety of products such as quinolinones [8], cycloheptene-6

On the application of 3d metals for C–H activation toward bioactive compounds: The key step for the synthesis of silver bullets

• Renato L. Carvalho,
• Amanda S. de Miranda,
• Mateus P. Nunes,
• Roberto S. Gomes,
• Guilherme A. M. Jardim and
• Eufrânio N. da Silva Júnior

Beilstein J. Org. Chem. 2021, 17, 1849–1938, doi:10.3762/bjoc.17.126

Reactions of N,3-diarylpropiolamides with arenes under superelectrophilic activation: synthesis of 4,4-diaryl-3,4-dihydroquinolin-2(1H)-ones and their derivatives

• Larisa Yu. Gurskaya,
• Diana S. Belyanskaya,
• Dmitry S. Ryabukhin,
• Denis I. Nilov,
• Irina A. Boyarskaya and
• Aleksander V. Vasilyev

Beilstein J. Org. Chem. 2016, 12, 950–956, doi:10.3762/bjoc.12.93

• superelectrophilic activation of the N-formyl group by TfOH in the reaction with benzene resulted in the formation of N-(diphenylmethyl)-substituted dihydroquinolinones. Keywords: alkynes; quinolinones; Friedel–Crafts reactions; superacids; superelectrophilic activation; Introduction Quinoline derivatives are a

• finally cyclized to 4,4-diaryl-3,4-dihydroquinolin-2(1H)-ones 2. It should be noted that quinolinones 3 do not react with arenes with formation of compounds 2 under superelectrophilic activation, and starting materials 3 remain unreacted [12][13]. Such 4,4-diaryl-3,4-dihydroquinolin-2-(1H)-ones 2 are very

• amides 1k,o gave regioselectively only 7-substituted quinolinones 2c,f (Table 1, entries 7, 8, 14 and 15) and 6,7-disubstituted quinolinones 2k,o (Table 1, entries 25 and 29), respectively. Concerning the arene component of this reaction, apart from benzene, chlorobenzene and 1,2-dichlorobenzene it may

New palladium–oxazoline complexes: Synthesis and evaluation of the optical properties and the catalytic power during the oxidation of textile dyes

• Rym Hassani,
• Mahjoub Jabli,
• Yakdhane Kacem,
• Jérôme Marrot,
• Damien Prim and
• Béchir Ben Hassine

Beilstein J. Org. Chem. 2015, 11, 1175–1186, doi:10.3762/bjoc.11.132

• hydroperoxometallic intermediaite 15 which decomposes to azoxy product 16 and palladium hydroxide complex 17. The degradation of the azoxy product 16 can afford quinolinones and diazonium salts as it established by many authors [38][39][40]. Conclusion In summary, new palladium-complexes using oxazolines as ligands

DBU-promoted carboxylative cyclization of o-hydroxy- and o-acetamidoacetophenone

• Wen-Zhen Zhang,
• Si Liu and
• Xiao-Bing Lu

Beilstein J. Org. Chem. 2015, 11, 906–912, doi:10.3762/bjoc.11.102

• in the reaction of o-acetamidoacetophenone. Keywords: acyl migration; carbon dioxide; carboxylation; cyclization; condensation; Introduction 4-Hydroxy-2H-chromen-2-ones and 4-hydroxy-2(1H)-quinolinones are key structural subunits found in many natural products [1], commercial drugs [2][3] and

• cyclization of o-hydroxy- and o-acetamidoacetophenones with carbon dioxide to give 4-hydroxy-2H-chromen-2-ones and 4-hydroxy-2(1H)-quinolinones, respectively, in moderate to good yields under mild reaction conditions. An acyl migration from the nitrogen to carbon is observed in the reaction of o

• )-quinolinone (Table 3). Using 4 equivalents DBU as base in DMSO at 80 °C, o-acetamidoacetophenone (3a) underwent the carboxylative cyclization reaction to provide 3-acetyl-4-methoxy-2(1H)-quinolinones 4a and 5a (Table 3, entry 1). Noteworthy, the acyl group was no longer bound to nitrogen in the product, which

Cationic gold(I) axially chiral biaryl bisphosphine complex-catalyzed atropselective synthesis of heterobiaryls

• Tetsuro Shibuya,
• Kyosuke Nakamura and
• Ken Tanaka

Beilstein J. Org. Chem. 2011, 7, 944–950, doi:10.3762/bjoc.7.105

• complex catalyzes the atropselective intramolecular hydroarylation of alkynes leading to enantioenriched axially chiral 4-aryl-2-quinolinones and 4-arylcoumarins with up to 61% ee. Keywords: asymmetric catalysis; axial chirality; gold; heterobiaryls; hydroarylation; Introduction Atropselective biaryl

• the highest enantioselectivity (Scheme 2) [42]. In addition, the cationic palladium(II)/axially chiral biaryl bisphosphine complexes were able to catalyze the asymmetric intramolecular hydroarylation of N-aryl-arylethynylamides leading to axially chiral 4-aryl-2-quinolinones, and the cationic

• -quinolinones and 4-arylcoumarins. Results and Discussion The reaction of N-benzyl-N-(2-naphthyl)propiolamide 1a, bearing a 2-methoxynaphthyl group at an alkyne terminus, was first investigated in the presence of a cationic gold(I)/(R)-BINAP complex (20 mol % Au). Although the reaction proceeded at room