Synthesis of functionalized γ-lactones via a three-component cascade reaction catalyzed by consecutive N-heterocyclic carbene systems

Zhao, Qian; Han, Bo; Wang, Biao; Leng, Hai‐Jun; Peng, Cheng; Huang, Wei

doi:10.1039/c5ra01254f

Cited by 19 publications

(5 citation statements)

References 68 publications

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“…In 2015, Huang reported a novel three-component coupling (see Scheme ). In this reaction, it is proposed that benzaldehyde ( 87 ) is dimerized via a benzoin reaction mediated by triazolylidene NHC B8 to give benzil 88 . Subsequent addition of α-bromoenal 44 and imidazolium precatalyst C1·HCl leads to the formation of the α,β-unsaturated acyl azolium intermediate 13 , which reacts with the enol form of benzil 88 .…”

Section: Cascades Involving Bond Formation At the β- And Acyl Carbonsmentioning

confidence: 99%

N-Heterocyclic Carbene Catalysis via the α,β-Unsaturated Acyl Azolium

2017

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First reported less than a decade ago, the α,βunsaturated acyl azolium has emerged as a central reactive intermediate for reaction discovery using N-heterocyclic carbene catalysis. In this Perspective, an introduction to the four main reactivity patterns accessible from this intermediate is provided. The Perspective is handled in a largely chronological fashion, with an emphasis on alternate approaches to the key intermediate and first-in-class reaction cascades. Finally, a brief discussion of emerging trends in this field of catalysis is presented. Although not exhaustive, the Perspective provides an overview of this active area of research and serves as a guide for future investigations.

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Section: Cascades Involving Bond Formation At the β- And Acyl Carbonsmentioning

confidence: 99%

N-Heterocyclic Carbene Catalysis via the α,β-Unsaturated Acyl Azolium

2017

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“…Zhao et al . reported two consecutive NHC catalytic systems ( L119–L122 ) and ( L123 and L124 ) combined in a one‐pot cascade reaction for the assembly of 2‐haloenals ( 157 ) and aromatic aldehydes ( 156 ) into a structurally complex γ‐lactone backbone ( 158 ) providing 10–64% yields as shown in Scheme . Authors described the first report of NHC‐catalyzed [3 + 2] annulation of α,β‐unsaturated acylazoliums with 1,2‐bisnucleophiles and trying to clarify the detailed reaction mechanism and explore whether this approach can be applied to asymmetric domino reactions.…”

Section: N‐heterocyclic Carbenes As Ligands and Their Metal Complexesmentioning

confidence: 99%

“…Delany et al [201] reported the use of novel NHC ligands (L127-L134) bearing a bulky yet highly electrondeficient N-aryl substituent for the first highly chemoselective intermolecular benzoin condensations between two nonidentical aromatic aldehydes (179)(180) yielding benzoins (181)…”

Section: April 2019mentioning

confidence: 99%

Recent Advances in the Schiff Bases and N‐Heterocyclic Carbenes as Ligands in the Cross‐Coupling Reactions: A Comprehensive Review

Kumar

2019

Journal of Heterocyclic Chem

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Cross‐coupling reactions, namely, the Suzuki–Miyaura, Heck, Sonogashira, Hiyama, Negishi, Kumada, and Hartwig–Buchwald, are the most powerful approaches in the formation of C–C, C–N, C–O, and C–S bonds for the complex organic scaffolds in drugs, natural products, organic materials, and fine chemicals. The nitrogen‐based ligands have upper hands in these reactions because they are air stable, inexpensive, and easier to handle than the phosphorous counterparts. In this perspective, Schiff bases and N‐heterocyclic carbenes have been explored extensively in terms of novel design and preparation as ligands in the coupling reactions. Facile recovery and reusability of these ligands make them eco‐friendly and economical. A comprehensive outline on the progress in Schiff bases–metal complexes and NHC–metal complexes that mediated cross‐coupling reactions with recent examples highlighted is reported (160 references).

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“…134-135 °C. R f = 0.2 ( petroleum ether/ethyl acetate 5 : 1); [α] 25 D = 21 (c = 0.1, CH 2 Cl 2 ); HPLC analysis: 95% ee [Daicel CHIRALPAK IA column, 20 °C, 254 nm, hexane/ i-PrOH = 80 : 20, 1.0 mL min −1 , 254 nm, 17.1 min (minor), 48.1 min (major)]; 1 H NMR (400 MHz, CDCl 3 ) δ 7.43 (d, J = 8.9 Hz, 2H), 7.24-7.11 (m,3H),3H),4.75 (dd,J = 8.8,2.0 Hz,1H),2H), 3.83 (s, 3H), 3.10 (dd, J = 16.7, 8.8 Hz, 1H), 2.80 (dd, J = 16.7, 2.1 Hz, 1H), 2.44 (s, 3H), 1.26 (t, J = 7.1 Hz, 3H). 13 C NMR (100 MHz, CDCl 3 ) δ 164.…”

Section: General Experimental Detailsmentioning

confidence: 99%