Synthesis of polysubstituted azetidines <i>via</i> cascade trifluoromethylation/cyclization of <i>N</i>-allyl ynamides

Zhou, Genlai; Su, Jingwen; Shang, Tianbo; Wang, Xiaojuan; Bai, Yihui; Yuan, Zheliang; Zhu, Gangguo

doi:10.1039/d1qo00559f

Cited by 15 publications

(7 citation statements)

References 66 publications

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“…In addition to these examples, various trifluoromethylation reactions with subsequent cyclizations of alkenes or alkynes have been reported. [125][126][127][128][129][130][131][132][133][134][135][136] Directed toward the synthesis of products with quaternary asymmetric carbons, the introduction of aryl and trifluoromethyl groups at the double bond of acrylamide compounds was developed by Liu et al [137] In this reaction, acrylamide 70 reacted with reagent 60 and arylboronic acid 71 in the presence of a copper catalyst and a bisoxazoline (Box) ligand bearing two benzyl groups to give α-arylated β-trifluoromethylated products 72 with a quaternary carbon (Scheme 28). Particularly, in the case of acrylamide with an alkyl group at the α-position, the corresponding product can be obtained with high enantioselectivity.…”

Section: Trifluoromethyl-and Trifluoromethylthiobenziodoxolesmentioning

confidence: 99%

“…Trifluoromethyl radical species are expected to be involved in this reaction, and the authors have confirmed by DFT calculations that 5‐ endo cyclization is favored compared to other possible cyclizations pathways. In addition to these examples, various trifluoromethylation reactions with subsequent cyclizations of alkenes or alkynes have been reported [125–136] …”

Section: Trifluoromethyl‐ and Trifluoromethylthiobenziodoxolesmentioning

confidence: 99%

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Recent Progress in Synthetic Applications of Cyclic Hypervalent Iodine(III) Reagents

2023

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Hypervalent iodine compounds have found broad application in modern organic chemistry as reagents and catalysts. Cyclic hypervalent iodine reagents based on the benziodoxole heterocyclic system have higher stability compared to their acyclic analogues, which makes possible the preparation and safe handling of the reagents with special ligands such as azido, cyano, and trifluoromethyl groups. Numerous iodine‐substituted benziodoxole derivatives have been prepared and utilized as reagents for transfer of the substituent on hypervalent iodine to organic substrate. Reactions of these reagents with organic substrates can be performed under metal‐free conditions, in the presence of transition metal catalysts, or using photocatalysts under photoirradiation conditions. In this review, we focus on the most recent synthetic applications of cyclic hypervalent iodine(III) reagents with the following ligands: N3, NHR, CN, CF3, SCF3, OR, OAc, ONO2, and C(=N2)CO2R. The review covers literature published mainly in the last 5 years.magnified image

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Section: Trifluoromethyl-and Trifluoromethylthiobenziodoxolesmentioning

confidence: 99%

Section: Trifluoromethyl‐ and Trifluoromethylthiobenziodoxolesmentioning

confidence: 99%

Recent Progress in Synthetic Applications of Cyclic Hypervalent Iodine(III) Reagents

2023

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“…In 2021, Zhu and co‐workers reported the construction of polysubstituted azetidine‐fused tricyclic compounds via cascade trifluoromethylation/cyclization of N ‐allyl sulfonyl ynamides (1,5‐enynes) with Togni's reagent II (Scheme 31). [58] This transformation was achieved under Cs 2 CO 3 ‐prompted or visible‐light induced conditions. Mechanistically, the single electron transfer between Cs 2 CO 3 and Togni's reagent II gives trifluoromethyl radical CF 3 ⋅, which adds to the double bond of ene‐ynamide to form alkyl radical 31‐A .…”

Section: Radical Cyclization Of 1n‐enynesmentioning

confidence: 99%

Radical Cascade Cyclization of Alkene‐Tethered Compounds: Versatile Approach towards Ring‐Fused Polycyclic Structures

Liu

Wang

2023

Asian J Org Chem

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Ring-fused polycyclic structures widely exist in a myriad of natural products and pharmaceutical molecules. Consequently, the construction of such structures from readily available substrates becomes an important researching topic in organic synthesis. Triggered by the addition of radicals to the (activated or unactivated) double bonds in alkenes, the subsequent intramolecular addition/cyclization leads to polycyclic compounds. Following this procedure, a variety of functionalized ring-fused structures were formed. Great achievements have been witnessed recently. Those works provided efficient, atom economy, and operational simple approaches toward versatile functionalized polycyclic structures from readily available alkene-based substrates.Here, we summarized the recent achievements on the formation of ring-fused polycyclic structures via the radicaltriggered cascade reactions of alkenes. Construction of polycyclic structures with no less than 3 fused rings developed during the last decade were included in this Review, corresponding mechanisms were also discussed.

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“…Togni reagent's I and II ( 31 , 38 ) have also been widely employed for ⋅CF 3 triggered intramolecular cyclizations (Scheme 44). In 2021, Bai, Yuan, Zhu, and coworkers reported the synthesis of CF 3 ‐containing azetidines by employing 31 and an organophotocatalyst [160] . Notably, the 4‐ exo‐dig radical cyclization represents a rare reaction motif and is postulated to occur through an alkenyl radical upon ⋅CF 3 addition.…”

Section: Trifluoromethylation (Cf3)mentioning

confidence: 99%

Recent Advances in Visible Light‐Mediated Radical Fluoro‐alkylation, ‐alkoxylation, ‐alkylthiolation, ‐alkylselenolation, and ‐alkylamination

Lin

Coe

Krishnamurti

et al. 2023

The Chemical Record

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In the last few years, many reagents and protocols have been developed to allow for the efficient fluorofunctionalization of a diverse set of scaffolds ranging from alkanes, alkenes, alkynes, and (hetero)arenes. The concomitant rise of organofluorine chemistry and visible light‐mediated synthesis have synergistically expanded the fields and have mutually benefitted from developments in both fields. In this context, visible light driven formations of radicals containing fluorine have been a major focus for the discovery of new bioactive compounds. This review details the recent advances and progress made in visible light‐mediated fluoroalkylation and heteroatom centered radical generation.

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Synthesis of polysubstituted azetidines via cascade trifluoromethylation/cyclization of N-allyl ynamides

Abstract: Traditional methods for the transformation of N-allyl ynamides rely on the formation of a ketenimine intermediate or its equivalent, while novel reaction modes remain to be developed. Herein, a cascade...

Cited by 15 publications

References 66 publications

Recent Progress in Synthetic Applications of Cyclic Hypervalent Iodine(III) Reagents

Recent Progress in Synthetic Applications of Cyclic Hypervalent Iodine(III) Reagents

Radical Cascade Cyclization of Alkene‐Tethered Compounds: Versatile Approach towards Ring‐Fused Polycyclic Structures

Recent Advances in Visible Light‐Mediated Radical Fluoro‐alkylation, ‐alkoxylation, ‐alkylthiolation, ‐alkylselenolation, and ‐alkylamination

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