Diastereodivergent Synthesis of Chiral 4-Fluoropyrrolidines (<i>exo</i> and <i>exo</i>′) Based on the Cu(II)-Catalyzed Asymmetric 1,3-Dipolar Cycloaddition

Kalita, Subarna Jyoti; Cheng, Feng; Fan, Qing‐Hua; Shibata, Norio; Huang, Yiyong

doi:10.1021/acs.joc.1c00509

Cited by 15 publications

(2 citation statements)

References 52 publications

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“…Fan and Huang and co-workers used Cu/L8 a to facilitate the enantioselective cycloaddition of α-fluoro-α,β-unsaturated arylketones 20 with azomethine ylides 1 to access chiral 4fluoropyrrolidines 21. [27] Under these conditions, a variety of imino esters, including aliphatic variants and α-fluoro-α,βunsaturated arylketones were gave exo-selective products in good yields with high levels of enantioselectivity, though the diasteroselectivity was slightly dependent on the sterics and electronics of both substrates (Scheme 12). Importantly, the use of DBU in toluene at 90 °C permitted the exo-selective products to be easily converted into the corresponding exo'-products.…”

Section: Metal-catalyzed [3 + 2] Azomethine Ylide Cycloadditionmentioning

confidence: 99%

Catalytic Enantioselective [3+2] Cycloaddition of N‐Metalated Azomethine Ylides

Kumar

Guiry

2023

Chemistry A European J

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Asymmetric [3 + 2] cycloaddition reactions are fascinating and powerful methods for the synthesis of enantioenriched pyrrolidines up to four stereocentres. Pyrrolidines are important compounds for both biology and organocatalytic applications. This review summarizes the most recent advances in the enantioselective synthesis of pyrrolidines by [3 + 2] cycloadditions of azomethine ylides using metal catalysis. It has been organized by the type of metal catalysis used and further arranged by the complexity nature of dipolarophile. The presentation of each reaction type highlights their advantages and limitations.

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Section: Metal-catalyzed [3 + 2] Azomethine Ylide Cycloadditionmentioning

confidence: 99%

Catalytic Enantioselective [3+2] Cycloaddition of N‐Metalated Azomethine Ylides

Kumar

Guiry

2023

Chemistry A European J

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“…Pyrrolidine azasugar derivatives were prepared via asymmetric [3+2] cycloadditions of azomethine ylides and β-silyl acrylates in the presence of Cu(I) complex Cu(CH 3 CN) 4 BF 4 [ 110 ]. Furthermore, Cu(II)-catalyzed asymmetric 1,3-dpolar cycloaddition of azomethine ylides and α-fuoro-α,β-unsaturated arylketone dipolarophiles yielded chiral 4-fluoropyrrolidines containing four contiguous stereogenic centers [ 111 ].…”

Section: Reactionsmentioning

confidence: 99%

Recent Advances in Synthetic Routes to Azacycles

Nguyen

Kim

2023

Molecules

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A heterocycle is an important structural scaffold of many organic compounds found in pharmaceuticals, materials, agrochemicals, and biological processes. Azacycles are one of the most common motifs of a heterocycle and have a variety of applications, including in pharmaceuticals. Therefore, azacycles have received significant attention from scientists and a variety of methods of synthesizing azacycles have been developed because their efficient synthesis plays a vital role in the production of many useful compounds. In this review, we summarize recent approaches to preparing azacycles via different methods as well as describe plausible reaction mechanisms.

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Stereodivergent Synthesis of Chiral Hydrobenzofuranpyrrolidines by Catalytic Asymmetric Dearomative Cyclization and Controlled Epimerization

Liu,

Huang,

Dai

et al. 2024

Adv Synth Catal

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A methodology to access stereoisomeric sets of products bearing multiple stereogenic centers is still a significant challenge in asymmetric catalysis. We present herein our experimental studies on the stereodivergent synthesis of chiral hydrobenzofuran‐fused pyrrolidines with three stereogenic centers via organocatalytic asymmetric dearomative cyclization and epimerization process. Chiral bifunctional thiourea catalyst could successfully promote the enantioselective dearomatization cyclization of 2‐nitrobenzofurans with o‐hydroxy aromatic aldimines, which enabled the synthesis of (3S,3aR,8bR)‐hydrobenzofuran[3.2]pyrrolidines in 79–92% yields with >20:1 stereoselectivities and 93–>99% enantio‐selectivities. While catalytic amount of DBU could induce the direct intramolecular epimerization of (3S,3aR,8bR)‐hydrobenzofuran[3.2] pyrrolidines to its diastereomers (3R,3aR,8bR)‐hydrobenzofuran[3.2] pyrrolidines in 72–87% yields without loss of stereoselectivities. The mechanistic pathways of the epimerization process were investigated by a series of control experiments study. This work provides an alternative and forward solution for the stereodivergent preparation of functionalized pyrrolidines with potential bioactivities.

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Diastereodivergent Synthesis of Chiral 4-Fluoropyrrolidines (exo and exo′) Based on the Cu(II)-Catalyzed Asymmetric 1,3-Dipolar Cycloaddition

Cited by 15 publications

References 52 publications

Catalytic Enantioselective [3+2] Cycloaddition of N‐Metalated Azomethine Ylides

Catalytic Enantioselective [3+2] Cycloaddition of N‐Metalated Azomethine Ylides

Recent Advances in Synthetic Routes to Azacycles

Stereodivergent Synthesis of Chiral Hydrobenzofuranpyrrolidines by Catalytic Asymmetric Dearomative Cyclization and Controlled Epimerization

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