First synthesis of acylated nitrocyclopropanes

• Kento Iwai,
• Rikiya Kamidate,
• Khimiya Wada,
• Haruyasu Asahara and
• Nagatoshi Nishiwaki

Beilstein J. Org. Chem. 2023, 19, 892–900, doi:10.3762/bjoc.19.67

• through an intramolecular aza-Wittig reaction, yielding cyclopropane-fused 2-quinolones [2]. A nitro group not only activates substrates and stabilizes the α-anion as an electron-withdrawing group but also acts as a nucleophile, electrophile, and leaving group, exhibiting diverse reactivities [3]. For

Copper-catalysed alkylation of heterocyclic acceptors with organometallic reagents

• Yafei Guo and
• Syuzanna R. Harutyunyan

Beilstein J. Org. Chem. 2020, 16, 1006–1021, doi:10.3762/bjoc.16.90

• ). When the method was applied to the ACA of Grignard reagents to N-substituted 2-quinolones, their lower reactivity led to a lower conversion. Performing the reaction in the presence of TMSBr resolved this and allowed the reaction to proceed for various Grignard reagents and substrates with an excellent

Gold-catalyzed post-Ugi alkyne hydroarylation for the synthesis of 2-quinolones

• Xiaochen Du,
• Jianjun Huang,
• Anton A. Nechaev,
• Ruwei Yao,
• Jing Gong,
• Erik V. Van der Eycken,
• Olga P. Pereshivko and
• Vsevolod A. Peshkov

Beilstein J. Org. Chem. 2018, 14, 2572–2579, doi:10.3762/bjoc.14.234

• . Subjecting these adducts to a gold-catalyzed intramolecular alkyne hydroarylation process allowed to efficiently construct the 2-quinolone core bearing a branched substituent on the nitrogen atom. Keywords: gold catalysis; hydroarylation; 2-quinolones; Ugi reaction; Introduction Quinoline and its oxidized

• -inflammatory [12][13] and anticancer [9][13][14][15][16][17][18][19]. In addition, 2-quinolones were identified as promising entities for the treatment of neuropathic pain [20][21][22] and erectile dysfunction [23]. Therefore, the elaboration of practical methodologies for the synthesis [24] and

• derivatives with most recent strategies focusing on the implementation of transition metal-catalyzed C–H activation methods [35][36]. One of the common approaches towards 2-quinolones 2 involves the intramolecular Friedel–Crafts hydroarylation [37][38] of N-arylamides of 3-substituted propynoic acids 1

Cobalt- and rhodium-catalyzed carboxylation using carbon dioxide as the C1 source

• Tetsuaki Fujihara and
• Yasushi Tsuji

Beilstein J. Org. Chem. 2018, 14, 2435–2460, doi:10.3762/bjoc.14.221

• coumarin derivatives were obtained in moderate-to-good yields. Notably, ketone (24e), ester (24d) moieties were tolerated in the reaction. In addition, 2-quinolones (24f and 24g) were obtained using alkynes bearing a Boc protected carbamate in place of the MOM protected ether. Scheme 23 shows a plausible

• -light-driven hydrocarboxylation of alkynes. Visible-light-driven synthesis of γ-hydroxybutenolides from ortho-ester-substituted aryl alkynes. One-pot synthesis of coumarines and 2-quinolones via hydrocarboxylation/alkyne isomerization/cyclization. Proposed reaction mechanism for the Co-catalyzed

The Elbs and Boyland- Sims peroxydisulfate oxidations

• E. J. Behrman

Beilstein J. Org. Chem. 2006, 2, No. 22, doi:10.1186/1860-5397-2-22

• -reaction and so increases the yield of the expected Elbs product, orotic acid 5-sulfate. Quinolones are another interesting case: 4-quinolones give reasonable yields of the expected 3-substitution products whereas 2-quinolones do not. [6] An explanation has been suggested which concerns the stability of

• facts imply a side-reaction in which the phenol serves as a catalyst in a set of reactions which leads to the consumption of peroxydisulfate. A particularly striking case is that of the 2-quinolones where no Elbs product is formed although peroxydisulfate is consumed at a reasonable rate. [6] Para

• poorly characterized. It seems clear that small proportions of starting materials, particularly for such substrates as the 2-quinolones, can undergo extensive oxidation probably involving catalysis by adventitious metal ions. Thus Walling and Buckler [17] reacted phenyl magnesium bromide with oxygen and