Triflic acid mediated sequential cyclization of ortho-alkynylarylesters with ammonium acetate

Domaradzki, Maciej E.; Liu, Xiaochen; Ong, Jiye; Yu, Gyeongah; Zhang, Gan; Simantov, Ariel; Perl, Eliyahu; Chen, Yu

doi:10.1016/j.tet.2020.131437

Cited by 8 publications

(5 citation statements)

References 75 publications

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“…The BF 3 ·Et 2 O-mediated cyclization of 2-alkynylbenzoates to isocoumarins has also been demonstrated by Du, Zhao, and their co-workers . Chen et al reported that the 2-alkynylbenzoate derivative can also be converted to isocoumarin in the presence of trifluoromethanesulfonic acid …”

Section: Results and Discussionmentioning

confidence: 86%

Synthesis, Structural, and Optical Properties of Azuleno[1,2-c]pyran-1-ones: Bro̷nsted Acid-Mediated Cyclization of 2-Azulenylalkynes

Shoji,

Sasahara,

Hamasaki

et al. 2023

J. Org. Chem.

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Pyrones and their aromatic ring-fused derivatives have gained significant attention due to their diverse biological activities and potential as foundational frameworks for advanced materials. In this paper, we describe a proficient approach for the preparation of azuleno[1,2-c]pyran-1-ones, which are difficult to produce by using conventional methods. The synthesis was achieved through Bro̷nsted acid-mediated cyclization of 2-azulenylalkynes. The structural and optical properties of azuleno[1,2-c]pyran-1-ones were characterized by single-crystal X-ray analysis, NMR, UV/vis, and fluorescence spectroscopies. Under acidic conditions, these compounds displayed notable spectral alterations and emission, distinct from their spectra in neutral medium. These results suggest that azuleno[1,2-c]pyran-1-ones hold great potential for applications in organic electronic materials and fluorescent pH sensors.

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Section: Results and Discussionmentioning

confidence: 86%

Synthesis, Structural, and Optical Properties of Azuleno[1,2-c]pyran-1-ones: Bro̷nsted Acid-Mediated Cyclization of 2-Azulenylalkynes

Shoji,

Sasahara,

Hamasaki

et al. 2023

J. Org. Chem.

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“…The obtained 4‐fluoroisocoumarin 2 a could be converted to 4‐fluoroisoquinoline 5 (Scheme 2). In this derivation, isoquinolinyl triflate derived from the lactam intermediate produced by treatment of 2 a with NH 4 OAc underwent Suzuki‐Miyaura coupling, yielding 5 in 77% yield in three steps without the purification of the intermediates [13b,14] . Although direct fluorination of isoquinoline with regioselectivity is expected to be difficult, this method allows the synthesis of 4‐fluoroisoquinolines in good yield and introduction of functional groups to the 1‐position through coupling reactions.…”

Section: Resultsmentioning

confidence: 99%

Fluorocyclization of 2‐Alkynylbenzoates: Synthesis of Fluorinated Isocoumarins by N‐Fluoropyridinium Salts

Sakagami,

Tsubouchi,

Saito

2024

Adv Synth Catal

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Fluorocyclization of heteroatom‐centred nucleophile‐tethered unsaturated compounds is one of the most powerful methods for the synthesis of fluorinated heterocycles. However, although these reactions have often been accomplished by using transition metal catalysts along with fluorine sources, such catalytic systems have not been applicable to the reaction of 2‐alkynylbenzoates. Herein, we describe metal‐free fluorocyclization of 2‐alkynylbenzoates by N‐fluoropyridinium salts. The present method allows the selective synthesis of 4‐fluoroisocoumarins and 3,4,4‐trifluoroisochromanones by minor modification of the reaction conditions. This report provides one of the few methods for the synthesis of fluorinated isocoumarin.

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“…Additional references cited within the Supporting Information (Ref. [29][30][31][32][33][34][35][36][37][38][39][40][41]).…”

Section: Methodsmentioning

confidence: 99%

Metal‐Free Synthesis of 4‐Bromoisocoumarins through Brominative Annulation of 2‐Alkynylaryloate Esters Using In Situ Generated Transient Bromoiodane

Sodoor,

Selvakumar

2023

Eur J Org Chem

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Herein we report, a facile and proficient protocol for the synthesis of 4‐bromoisocoumarins via brominative annulation of 2‐alkynylaryloate esters with in situ generated bromoiodane using simple hypervalent iodine reagent as mild oxidant and potassium bromide as the halogen source. Using this method, a broad range of valuable halogenated isocoumarins can be obtained with excellent yield at room temperature. Also, this reaction takes place in the absence of any metal catalyst and exhibits high functional group tolerance. Besides, the reaction can also be extended to the gram scale, and a catalytic approach was also demonstrated. Additionally, the prepared 3‐bromoisocoumarins were further transformed into important synthetic compounds.

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Triflic acid mediated sequential cyclization of ortho-alkynylarylesters with ammonium acetate

Cited by 8 publications

References 75 publications

Synthesis, Structural, and Optical Properties of Azuleno[1,2-c]pyran-1-ones: Bro̷nsted Acid-Mediated Cyclization of 2-Azulenylalkynes

Synthesis, Structural, and Optical Properties of Azuleno[1,2-c]pyran-1-ones: Bro̷nsted Acid-Mediated Cyclization of 2-Azulenylalkynes

Fluorocyclization of 2‐Alkynylbenzoates: Synthesis of Fluorinated Isocoumarins by N‐Fluoropyridinium Salts

Metal‐Free Synthesis of 4‐Bromoisocoumarins through Brominative Annulation of 2‐Alkynylaryloate Esters Using In Situ Generated Transient Bromoiodane

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