Four-Membered Heterocycles

Kumar, M.; Gupta, Vandana

doi:10.1007/978-3-642-72276-9_7

Cited by 16 publications

(12 citation statements)

References 93 publications

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“…In addition to [4,3,0] ring systems, we examined the feasibility for the formation of [4,4,0] ring systems. We were delighted to find the formation of 4q when 3q bearing a longer tether was employed.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…Likewise, the substrates bearing various heteroatoms in the tethers gave the corresponding bicycles (4r−4t). The diastereoselectivity for the [4,4,0] system could also be accounted by the allylic strain (see Figure S1).…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…1,2 Fourmembered rings, including carbocycles and heterocycles, present unique challenges for synthesis owing to their high ring strains. 3,4 [2 + 2] cycloaddition has proven to be an efficient approach, for which ultraviolet (UV) irradiation 5 and transition metal catalysis 6 have been extensively studied. Among the synthetic methods for these small size rings, it is notable that the synthesis of azetines is scarce with only a few methods reported.…”

Section: ■ Introductionmentioning

confidence: 99%

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Synthesis of Bicyclic N-Heterocycles via Photoredox Cycloaddition of Imino-Alkynes and Imino-Alkenes

Ryou

Park

et al. 2021

ACS Catal.

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Cycloaddition reactions offer great advantages regarding atom and step economy for the construction of various carbocycles and heterocycles. While the recent development based on sensitized visible light photocatalysis allowed the synthesis of azetidines via imine-alkene [2 + 2] cycloaddition, imine-alkyne [2 + 2] cycloaddition under visible light photocatalysis has not been reported. In this regard, we report the synthesis of pyrrolizidinones based on intramolecular imine-alkyne [2 + 2] cycloaddition under visible light photocatalysis. This redox-neutral reaction involves formal imine-alkyne metathesis followed by redox-mediated annulation with concomitant rearrangement. In contrast, the use of imino-alkenes provides dihyro-1,4-oxazines via an alternative [4 + 2] cycloaddition pathway. The proposed reaction mechanisms were supported by control experiments and DFT calculations.

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Section: ■ Results and Discussionmentioning

confidence: 99%

Section: ■ Results and Discussionmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

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Synthesis of Bicyclic N-Heterocycles via Photoredox Cycloaddition of Imino-Alkynes and Imino-Alkenes

Ryou

Park

et al. 2021

ACS Catal.

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“…In the form of metal complex, several drugs have been modified based on toxicological and pharmacological properties. Schiff bases are flexible –CH = N-(imine) containing compounds with an extensive biological activity and metal integration in the form of complexes exhibiting some degree of antibacterial, antifungal, antitumor and anti-inflammatory activities [ 32 , 33 ].…”

Section: Introductionmentioning

confidence: 99%

2-methoxy-4-(((5-nitropyridin-2-yl)imino)methyl)phenol Schiff base ligand and its Cu(II) and Zn(II) complexes: synthesis, characterization and biological investigations

Deepika

Vinusha²,

Begum

et al. 2022

Heliyon

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“…Cyclic ethers are important structural elements in organic chemistry, and they can be found at the core of molecules ranging from common solvents to complex natural products . The majority of synthetic approaches to cyclic ethers are based upon reactions of nucleophilic oxygen with electrophilic carbon (Figure a–d). − …”

Section: Introductionmentioning

confidence: 99%

Synthesis of α-Cyano and α-Sulfonyl Cyclic Ethers via Intramolecular Reactions of Peroxides with Sulfone- and Nitrile-Stabilized Carbanions

Horn

Dussault

2019

J. Org. Chem.

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The intramolecular reaction of carbon nucleophiles with oxygen-centered electrophiles has been little explored outside of nucleophilic epoxidation. We now report the synthesis of sulfonyl-and cyano-substituted oxacycles via intramolecular reaction of sulfone-and nitrile-stabilized carbanions with dialkyl peroxides, triethylsilyl/alkyl peroxides, and monoperoxyacetals. The cyclizations are successfully applied to synthesize oxetanes, tetrahydrofurans, and tetrahydropyrans but fail for oxepanes. Cyclizations involving the relatively stabilized anion derived from a benzylic nitrile proceed in high yields for a variety of peroxides, including those in which the electrophilic oxygen is formally isobutyl or neopentyl. Corresponding cyclizations of an alkanenitrile are successful with both dialkyl and alkyl silyl peroxides but demonstrate much greater variability in yields. Reactions of sulfone-containing substrates are successful only with dialkyl peroxides. The success of reactions appears to be strongly influenced by the rate of peroxide decomposition, which appears to be highest for reactions involving poorly stabilized anions. The significant variation in diastereoselectivity observed for different classes of peroxide on a common framework suggests the possibility of substrate-dependent reaction mechanisms.

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Four-Membered Heterocycles

Cited by 16 publications

References 93 publications

Synthesis of Bicyclic N-Heterocycles via Photoredox Cycloaddition of Imino-Alkynes and Imino-Alkenes

Synthesis of Bicyclic N-Heterocycles via Photoredox Cycloaddition of Imino-Alkynes and Imino-Alkenes

2-methoxy-4-(((5-nitropyridin-2-yl)imino)methyl)phenol Schiff base ligand and its Cu(II) and Zn(II) complexes: synthesis, characterization and biological investigations

Synthesis of α-Cyano and α-Sulfonyl Cyclic Ethers via Intramolecular Reactions of Peroxides with Sulfone- and Nitrile-Stabilized Carbanions

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