Au-catalyzed ring-opening reactions of 2-(1-alkynyl-cyclopropyl)pyridines with nucleophiles

2015 ◽  
Vol 13 (17) ◽  
pp. 4855-4858 ◽  
Author(s):  
Ren-Rong Liu ◽  
Shi-Chun Ye ◽  
Chuan-Jun Lu ◽  
Bin Xiang ◽  
Jianrong Gao ◽  
...  
Keyword(s):  
Ring Opening ◽  
Bond Cleavage ◽  
Mild Conditions ◽  
Efficient Access ◽  
Ring Opening Reactions ◽  
Novel Method

A novel method for the C–C bond cleavage of cyclopropanes was developed by gold-catalyzed cycloisomerization of 2-(1-alkynyl-cyclopropyl)pyridine with nucleophiles, which provides efficient access to structurally diverse indolizines under mild conditions.

Oxidative ring-opening of 3-aminoindazoles for the synthesis of 2-aminobenzoates

2018 ◽  
Vol 5 (22) ◽  
pp. 3245-3249 ◽  
Author(s):  
Yao Zhou ◽  
Qiuling Song
Keyword(s):  
Ring Opening ◽  
Bond Cleavage ◽  
Mild Conditions

A novel oxidative ring-opening of 3-aminoindazoles based on N–N bond cleavage was developed, in which various 2-aminobenzoates were obtained in good yields under mild conditions.

Synthesis ofC-Unsubstituted 1,2-Diazetidines and Their Ring-Opening Reactions via Selective N–N Bond Cleavage

2018 ◽  
Vol 83 (16) ◽  
pp. 9497-9503 ◽  
Author(s):  
Hetti Handi Chaminda Lakmal ◽  
Joanna Xiuzhu Xu ◽  
Xue Xu ◽  
Bassem Ahmed ◽  
Christopher Fong ◽  
...  
Keyword(s):  
Ring Opening ◽  
Bond Cleavage ◽  
Ring Opening Reactions

Thiophene ring-opening reactions IV. Facile generation of novel ethyl 4-hydroxy-6-thioxonicotinate─1,3,4- thiadiazoline hybrids

2021 ◽  
Vol 18 ◽  
Author(s):  
Mohammed M. Abadleh ◽  
Ahmad H. Abdullah ◽  
Jalal A. Zahra ◽  
Salim S. Sabri ◽  
Firas F. Awwadi ◽  
...  
Keyword(s):  
Single Crystal ◽  
Spectral Data ◽  
1H Nmr ◽  
13C Nmr ◽  
Ring Opening ◽  
Thiophene Ring ◽  
X Ray Diffraction ◽  
X Ray ◽  
Mild Conditions ◽  
Ring Opening Reactions

: A set of triethylammonium 4-oxo-6-pyridinethiolate–1,3,4-thiadiazoline hybrids (3a-e) were prepared via the reaction of ethyl 2-chloro-6-cyclopropyl-3- nitro-4-oxothieno[2,3-b]pyridine- 5-carboxylate (2) with the appropriate thiobenzoyl- hydrazide (1a-e) in acetonitrile and triethylamine. These hybrids were readily converted, under neutral mild conditions, into the corresponding 4-hydroxy-6-thioxopyridine –thiadiazoline hybrids (5a-e). The structures of the latter set are supported by HRMS, 1H NMR and 13C NMR spectral data and further confirmed by single-crystal X-ray diffraction studies. Alkylation of these hybrids in the presence of triethylamine occurred exclusively at the 6-thioxosulfur, yielding the respective 6-sulfanyl derivatives (6a-c).

scholarly journals Catalytic Ring Opening of α-Epoxyketones Using DDQ in Methanol Solution at Room Temperature and under Reflux Conditions in Excellent Yields

2007 ◽  
Vol 62 (8) ◽  
pp. 1030-1034 ◽  
Author(s):  
Hamid R. Memarian ◽  
Ali Saffar-Teluri ◽  
Mohsen Khosravi-Babadi
Keyword(s):  
Electron Acceptor ◽  
Ring Opening ◽  
Room Temperature ◽  
Bond Cleavage ◽  
Methanol Solution ◽  
Effect Of Temperature ◽  
Cyclic Voltammetric ◽  
Ring Opening Reactions ◽  
Voltammetric Studies ◽  
Cyclic Voltammetric Studies

Catalytic ring opening reactions of α-epoxyketones by 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) in methanol solution at r. t. and under reflux conditions resulted in the formation of α-hydroxy-β -methoxyketones through Cβ -O bond cleavage in excellent yields.Whereas the type and nature of the additional substituent affects the rate of ring opening, the effect of temperature has an extreme influence on the rate of reactions. Cyclic voltammetric studies of DDQ at 15 °C and 33 °C support the increased electron-acceptor ability of DDQ by the increasing of temperature.

Divergent Synthesis of Five-Membered Nitrogen Heterocycles via Cascade Reactions of 4-Arylfuroxans

Synthesis ◽  
2020 ◽  
Vol 52 (18) ◽  
pp. 2667-2678
Author(s):  
Leonid L. Fershtat ◽  
Daniil A. Chaplygin ◽  
Ivan V. Ananyev ◽  
Nina N. Makhova
Keyword(s):  
Ring Opening ◽  
Heterocyclic Compounds ◽  
Nitrogen Heterocycles ◽  
Cascade Reactions ◽  
Materials Chemistry ◽  
One Pot ◽  
Mild Conditions ◽  
Novel Method ◽  
High Yields

A novel method for the synthesis of a diverse series of functionally substituted five-membered heterocyclic compounds via atom-economic, regio-, and diastereoselective one-pot reaction cascade was developed. This approach involves a ring opening in 4-arylfuroxans to α-oximinoarylacetonitrile oxides followed by [3+2] cycloaddition to various dipolarophiles to afford multisubstituted isoxazoles and isoxazolines. Subsequent azole–azole rearrangement of (oximino)isoxazolines/-isoxazoles, which can be conducted in a one-pot manner, results into functionally substituted furazans formation. The developed protocol is operationally simple, proceeds in mild conditions and with high yields of target heterocyclic systems. Overall, this study represents a new mode of isoxazole and 1,2,5-oxadiazole functionalization strategy, which is useful in medicinal and materials chemistry.

Nickel-Catalyzed Asymmetric Cross-Electrophile Coupling Reactions

Synlett ◽  
2020 ◽  
Vol 31 (19) ◽  
pp. 1843-1850 ◽  
Author(s):  
Chuan Wang ◽  
Youxiang Jin
Keyword(s):  
Asymmetric Catalysis ◽  
Carbonyl Compounds ◽  
Ring Opening ◽  
Research Field ◽  
Optically Active ◽  
Coupling Reactions ◽  
Mild Conditions ◽  
Novel Approach ◽  
Ring Opening Reactions ◽  
Two Component

The merger of cross-electrophile coupling and asymmetric catalysis provides a novel approach to the preparation of optically active compounds. This method is often endowed with high step economy, mild conditions, and excellent tolerance of functional groups. Recent advances in the research field of nickel-catalyzed asymmetric cross-electrophile coupling reactions are highlighted in this concise Synpacts article.1 Introduction2 Asymmetric Cross-Electrophile Coupling Reactions between Organohalides3 Asymmetric Electrophilic Ring-Opening Reactions4 Asymmetric Electrophilic Difunctionalization of Alkenes4.1 Two-Component Electrophilic Difunctionalization of Alkenes Involving Arylnickelation as an Enantiodetermining Step4.2 Two-Component Electrophilic Difunctionalization of Alkenes Involving Carbamoylnickelation as an Enantiodetermining Step4.3 Three-Component Electrophilic Difunctionalization of Alkenes5 Asymmetric Electrophilic Functionalization of Carbonyl Compounds6 Summary

Asymmetric catalysis in aqueous media

2007 ◽  
Vol 79 (2) ◽  
pp. 235-245 ◽  
Author(s):  
Shū Kobayashi
Keyword(s):  
Asymmetric Catalysis ◽  
Lewis Acids ◽  
Ring Opening ◽  
Acid Catalysis ◽  
Aqueous Media ◽  
Asymmetric Reactions ◽  
Epoxide Ring ◽  
Mild Conditions ◽  
Ring Opening Reactions ◽  
Bipyridine Ligand

Lewis acid catalysis has attracted much attention in organic synthesis because of unique reactivity and selectivity attained under mild conditions. Although various kinds of Lewis acids have been developed and applied in industry, these Lewis acids must be generally used under strictly anhydrous conditions. The presence of even a small amount of water handles the reactions owing to preferential reactions of the Lewis acids with water rather than the substrates. In contrast, rare earth and other metal complexes have been found to be water-compatible. Several catalytic asymmetric reactions in aqueous media, including hydroxymethylation of silicon enolates with an aqueous solution of formaldehyde in the presence of Sc(OTf)3-chiral bipyridine ligand or Bi(OTf)3-chiral bipyridine ligand, Sc- or Bi-catalyzed asymmetric meso-epoxide ring-opening reactions with amines, and asymmetric Mannich-type reactions of silicon enolates with N-acylhydrazones in the presence of a chiral Zn catalyst have been developed. Water plays key roles in these asymmetric reactions.

scholarly journals Enantioselective cyanation via radical-mediated C–C single bond cleavage for synthesis of chiral dinitriles

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Tao Wang ◽  
Yi-Ning Wang ◽  
Rui Wang ◽  
Bo-Chao Zhang ◽  
Chi Yang ◽  
...  
Keyword(s):  
Ring Opening ◽  
Bond Cleavage ◽  
Catalyst Loading ◽  
Small Ring ◽  
Single Bond ◽  
Asymmetric Transformations ◽  
Mild Conditions ◽  
Ring Opening Reaction ◽  
High Yields ◽  
Low Catalyst Loading

AbstractRing-opening reaction via selective cleavage of C–C bond is known as a powerful strategy for construction of complex molecules. Complementary to the ionic process focusing on mostly small ring systems, radical-mediated C–C bond cleavage offers a solution for further diverse enantioselective functionalization benefited from its mild conditions, whereas such asymmetric transformations are still limited to three-membered rings so far. Herein, we describe radical-mediated ring-opening and enantioselective cyanation of four- and five-membered cycloketone oxime esters to access chiral 1,5- and 1,6-dinitriles. Employment of dual photoredox/copper catalysis is essential for the asymmetric ring-opening cyanation of cyclopentanone oxime esters. Both reactions proceed under mild conditions giving chiral dinitriles in high yields and enantioselectivity with low catalyst loading and broad substrate scope. The products dinitriles can be converted to valuable optically active diamides and diamines. Mechanistic studies indicate that the benzylic radical generated via C–C single bond cleavage is involved in the catalytic cycle.

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