Lactamization of sp<sup>2</sup> C−H Bonds with CO<sub>2</sub>: Transition‐Metal‐Free and Redox‐Neutral

Zhang, Zhen; Liao, Li‐Li; Yan, Shusen; Wang, Lei; He, Yanli; Ye, Jian‐Heng; Li, Jing; Zhi, Yong‐Gang; Yu, Da‐Gang

doi:10.1002/ange.201602095

Cited by 40 publications

(4 citation statements)

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“…[20] Building on the ability of aromatic amines to trap carbon dioxide under basic conditions, Yu and co-workersr eported in 2016 ac ascade process for the one-pot synthesis of 2-quinolines 34 (Scheme 8). [22] The reactions, promoted by 4.5 equivalents of NaOtBu, proceed smoothly furnishing aw ide range of 3-and 4-substituted2 -quinolines 34 in good to high yields. As showni nS cheme 8, the reactioni sa lso amenable to different substituted heterocyclic scaffolds such as 34 d.…”

Section: Carboxylation Of C(sp 2 )Aromatic Substratesmentioning

confidence: 99%

“…[22] Scheme9.a) TBD-promoted CO 2 fixation with aniline derivatives developed by Xi and co-workers. After CO 2 activation by meanso ft he reversible for-Scheme8.Base-mediated CO 2 fixation with aniline derivatives developed by Yu and co-workers.…”

Section: Carboxylation Of C(sp 2 )Aromatic Substratesmentioning

confidence: 99%

“…After CO 2 activation by meanso ft he reversible for-Scheme8.Base-mediated CO 2 fixation with aniline derivatives developed by Yu and co-workers. [22] Scheme9.a) TBD-promoted CO 2 fixation with aniline derivatives developed by Xi and co-workers. [23] b) Synthesis of 7-membered 6-dibenzoazepinone derivatives.…”

Section: Carboxylation Of C(sp 2 )Aromatic Substratesmentioning

confidence: 99%

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Transition Metal‐Free CO₂ Fixation into New Carbon–Carbon Bonds

et al. 2018

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CO is the ultimate renewable carbon source on Earth and the essential C building block for carbohydrate biosynthesis in photosynthetic organisms. Modern synthetic chemistry is facing the key challenge of developing fundamental transformations, such as C-C bond formation, in a sustainable and efficient manner from renewable sources. In this Minireview, the most significant methods recently reported for CO fixation under transition metal-free conditions are summarized, organized into three different chapters according to the nature of the chemical transformation that forges the new C-C bond. The focus is on the mechanistic aspects of the different CO activation modes, with specific attention to those systems that operate under catalytic conditions.

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Section: Carboxylation Of C(sp 2 )Aromatic Substratesmentioning

confidence: 99%

Section: Carboxylation Of C(sp 2 )Aromatic Substratesmentioning

confidence: 99%

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Transition Metal‐Free CO₂ Fixation into New Carbon–Carbon Bonds

et al. 2018

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“…For example, the groups of Yamada and Zhang independently reported the synthesis of 4‐hydroxyquinolin‐2(1 H )‐ones via a silver‐ or copper‐catalyzed incorporation of CO 2 into o‐alkynylanilines (Scheme , a). Yu and co‐workers developed a transition‐metal‐free lactamization of sp 2 C−H bonds with CO 2 to generate diverse 2‐quinolinones under redox‐neutral conditions (Scheme , b) . Although great progress has been made in this field, to the best of our knowledge, no straightforward approach has been developed for the synthesis of 4‐aryloxy‐2‐quinolinones by using CO 2 as the carbonyl source thus far.…”

Section: Figurementioning

confidence: 99%

Silver-Promoted Coupling of Carbon Dioxide,o-Alkynylanilines and Diaryliodonium Salts: Straightforward Access to 4-Aryloxy-2-quinolinones

Guo

Xiong

et al. 2017

ChemistrySelect

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A silver-promoted three-component reaction of carbon dioxide, o-alkynylanilines and diaryliodonium salts using 1,4-diazabicyclo[2.2.2]octane (DABCO) as the base has been developed for the first time, which provides an efficient and straightforward protocol for the synthesis of a wide range of 4-aryloxysubstituted 2-quinolinones in moderate to excellent yields. Diverse functional groups such as halo, trifluoromethyl, cyano and nitro are well tolerated. Mechanistic studies indicated that 4-hydroxyl-2-quinolinone generated in-situ from o-alkynylanilines and carbon dioxide might be the key intermediate for the reaction.2-Quinolinones represent an important class of nitrogencontaining heterocycles frequently found in a variety of biologically active natural products and pharmaceutically interesting compounds, such as 3-O-methylviridicatin, laquinimod and tipifarnib ( Figure 1). [1] Moreover, 2-quinolinones can serve as useful intermediate in various synthetic transformations. [2] Conventionally, 2-quinolinones have been prepared mainly through two methods: a) the reaction of anilines with bdicarbonyl compounds, such as ethyl acetoacetate, [3] malonic esters, [4] malonic acid, [5] or Meldrum's acid; [6] and b) the condensation of o-aminobenzaldehydes [7] or o-aminobenzophenones [8] with b-dicarbonyl compounds. However, these procedures need strong acids or bases and suffer from disadvantages such as limited substrate scope and low efficiency. Therefore, the development of new and efficient methods for the construction of these important molecules is of great significance.In the past decade, many elegant strategies have been developed for accessing different kinds of 2-quinolinones via transition metal catalysis, including intramolecular cyclization reactions via C-C [9] or CÀN bond [10] formation, Pd-catalyzed formal [3 + 3] cyclizations, [11] Ir- [12a] or Ni-catalyzed [12b] [4 + 2] annulations, and Pd-catalyzed [5 + 1] oxidative cyclocarbonylation. [13] Interestingly, Dong et al. reported a Rh-catalyzed [5 + 2 À 1] transformation between isatins and alkynes for the synthesis of 2-quinolinones. [14] Multi-component reaction strategy has also been applied to the synthesis of these rings, such as Pd-or Rh-catalyzed [3 + 2 + 1] [15] and [4 + 1 + 1] [16] reactions.Notably, carbon dioxide (CO 2 ) has recently emerged as an attractive carbonyl source for the construction of 2-quinolinones due to its nontoxicity, abundance and recyclability. [17] For example, the groups of Yamada [18a] and Zhang [18b] independently reported the synthesis of 4-hydroxyquinolin-2(1H)-ones via a silver-or copper-catalyzed incorporation of CO 2 into oalkynylanilines (Scheme 1, a). Yu and co-workers developed a transition-metal-free lactamization of sp 2 CÀH bonds with CO 2 to generate diverse 2-quinolinones under redox-neutral conditions (Scheme 1, b). [18c] Although great progress has been made in this field, to the best of our knowledge, no straightforward approach has been developed for the synthesis of 4-aryloxy-2-quinolinones...

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Divergent Synthesis of Quinoline Derivatives via [5+1] Annulation of 2‐Isocyanochalcones with Nitroalkanes

Bao

Liu

et al. 2018

Adv Synth Catal

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An unprecedented substrate‐dependent [5+1] annulation of 2‐isocyanochalcones with nitroalkanes was developed for the efficient synthesis of functionalized quinolines and 3‐nitrodihydroquinolines. This transformation delivers both the aromatic and dihydroquinolines by selectively elimination or retention of the nitro group. Moreover, 3‐nitroquinolines and tricyclic pyrrolo[2,3‐c]quinolines were conveniently constructed from the resulting 3‐nitrodihydroquinolines through a single operation, respectively.magnified image

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Lactamization of sp² C−H Bonds with CO₂: Transition‐Metal‐Free and Redox‐Neutral

Cited by 40 publications

References 75 publications

Transition Metal‐Free CO₂ Fixation into New Carbon–Carbon Bonds

Transition Metal‐Free CO₂ Fixation into New Carbon–Carbon Bonds

Silver-Promoted Coupling of Carbon Dioxide,o-Alkynylanilines and Diaryliodonium Salts: Straightforward Access to 4-Aryloxy-2-quinolinones

Divergent Synthesis of Quinoline Derivatives via [5+1] Annulation of 2‐Isocyanochalcones with Nitroalkanes

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Lactamization of sp2 C−H Bonds with CO2: Transition‐Metal‐Free and Redox‐Neutral

Cited by 40 publications

References 75 publications

Transition Metal‐Free CO2 Fixation into New Carbon–Carbon Bonds

Transition Metal‐Free CO2 Fixation into New Carbon–Carbon Bonds

Silver-Promoted Coupling of Carbon Dioxide,o-Alkynylanilines and Diaryliodonium Salts: Straightforward Access to 4-Aryloxy-2-quinolinones

Divergent Synthesis of Quinoline Derivatives via [5+1] Annulation of 2‐Isocyanochalcones with Nitroalkanes

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Lactamization of sp² C−H Bonds with CO₂: Transition‐Metal‐Free and Redox‐Neutral

Transition Metal‐Free CO₂ Fixation into New Carbon–Carbon Bonds

Transition Metal‐Free CO₂ Fixation into New Carbon–Carbon Bonds