The action of carbenes on N-heterocycles (I)

Zugrăvescu, I.; Rucinschi, E.; Surpateanu, Gheorghe

doi:10.1016/s0040-4039(01)97872-4

Cited by 30 publications

(11 citation statements)

References 3 publications

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“…A literature survey show that the reactions of imidazolium ylides with activated symmetrically or non symmetrically substituted alkynes occur usually as a typically Huisgen 3+2 cycloadditions [12,[22][23][24][25][26][27][28][29], leading to the corresponding fused azaheterocycles type II, Scheme 1.…”

Section: Resultsmentioning

confidence: 99%

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Imidazolium ylides: cycloaddition versus hydrolisis

Diaconu¹,

Mangalagiu²,

Mantu³

et al. 2019

Studia UBB Chemia

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IMIDAZOLIUM YLIDES: CYCLOADDITION versus HYDROLISIS DUMITRELA CUCU a,b , VIOLETA MANGALAGIU b , DORINA AMARIUCAI-MANTU a , VASILICHIA ANTOCI a , IONEL I. MANGALAGIU a,b, * ABSTRACT. Reactions of imidazolium ylides with dimethyl acetylenedicarboxylate in polar solvents (methanol) were studied. In the competition between cycloaddition versus hydrolysis, the last one prevails leading to base heterocycle, diene structures and benzoate esters. A feasible reaction mechanism is presented. When fused pyrrolo-imidazole derivatives are desirable to be obtained, polar solvents should be avoided.

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Section: Resultsmentioning

confidence: 99%

“…Despite of their huge importance from pharmacological, industrial, and synthetic points of view, there are only a limited method for the synthesis of the imidazole derivatives, cycloaddition reactions of cycloimmonium ylides to variously dipolarophiles (activated alkenes and alkynes) being one choice [12,13].…”

Section: Introductionmentioning

confidence: 99%

Imidazolium ylides: cycloaddition versus hydrolisis

Diaconu¹,

Mangalagiu²,

Mantu³

et al. 2019

Studia UBB Chemia

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“…[124] However, CϪN insertion to give 132 was observed on photolysis of 69 in the presence of allyldimethylamine, [124b] and the stable ylide 133 was obtained by heating ethyl diazoacetate with isoquinoline (Scheme 22). [125] The carbenes 135, generated from 134, were trapped by the o-diakylamino group (Ǟ 137) competitively with Wolff rearrangement (Ǟ 136). [126] The structures of both the ammonium ylide 137 and the mesoionic compound 138 were confirmed by X-ray analysis.…”

Section: Competing Reactionsmentioning

confidence: 99%

100 Years of the Wolff Rearrangement

2002

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The conversion of α‐diazo ketones into ketenes, and products derived therefrom, was discovered by Wolff in 1902. Major applications of the Wolff rearrangement, such as the Arndt−Eistert reaction (homologation of carboxylic acids) and the ring contraction of cyclic ketones, have been with us for some while. Nevertheless, substantial progress has been made recently. The reaction mechanism has been explored by means of matrix isolation, time‐resolved spectroscopy, and computation. Full retention of configuration of the migrating group has been established by using enantioselective chromatography. The Arndt−Eistert reaction has witnessed a renaissance in the field of natural products, in particular β‐amino acids and β‐peptides. Ring‐contracting Wolff rearrangements and ketene cycloadditions have been applied in syntheses of increasingly complex, biologically active target molecules. These accomplishments, as well as unsolved problems, are addressed in the present review. (© Wiley‐VCH Verlag GmbH, 69451 Weinheim, Germany, 2002)

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“…With the rapid developments in synthetic photochemistry, the photochemical reaction of diazo compounds via free carbene intermediates has been re-emerged in the past years. [14,15] The early example of the formation of pyridinium ylide from diazo compounds and pyridines under photocatalysis or thermocatalysis was disclosed by Platz [16] and Surpateanu, [17] respectively. However, the only reaction with isolated cycloadduct was reported by Platz: photolysis of diazirine 1 with pyridine 2 a to produce 3 in about 30% yield via sequential formation of free carbene, pyridinium ylide, and [3 + 2]-cycloaddition with dimethylacetylenedicarboxylate (DMAD) followed by aromatization via elimination of a molecule of HCl (Scheme 4.…”

Section: Photochemical/thermo-induced [3 + 2]-cycloaddition Of Pyridimentioning

confidence: 99%

[3+2]‐Cycloaddition of Catalytically Generated Pyridinium Ylide: A General Access to Indolizine Derivatives

Dong

2020

Asian J Org Chem

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Pyridinium ylide is a versatile building block in synthetic organic chemistry, especially in the synthesis of N‐heterocycles. In this minireview, we have summarized the advances of [3+2]‐cycloaddition of catalytically generated pyridinium ylide for the synthesis of indolizines (since 1970s). Accordingly, the ylide discussed in this article is generated in situ from carbene precursors and N‐heteroarenes under catalytic conditions, including photocatalysis/thermocatalysis, and metal‐catalysis. The metal‐catalyzed version is the main focus, which is classified and summarized based on the type of dipolarophiles, alkyne and alkene, each class is further subdivided according to the metal catalysts used in these reactions. The analogous [3+2]‐cycloaddition of vinyl metal carbene with pyridines, the formation of pyridinium ylide with other type of carbene precursors or with different N‐heteroarenes, have been also included herein separately.

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The action of carbenes on N-heterocycles (I)

Cited by 30 publications

References 3 publications

Imidazolium ylides: cycloaddition versus hydrolisis

Imidazolium ylides: cycloaddition versus hydrolisis

100 Years of the Wolff Rearrangement

[3+2]‐Cycloaddition of Catalytically Generated Pyridinium Ylide: A General Access to Indolizine Derivatives

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