Gold-Catalyzed Oxime–Oxime Rearrangement

Guven, Sinem; Özer, Merve Sinem; Kaya, Serpil; Mengeş, Nurettin; Balcı, Metin

doi:10.1021/acs.orglett.5b01041

Cited by 43 publications

(16 citation statements)

References 67 publications

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“…Initially, based on our previous works on the synthesis of azaheterocyclic compounds, [15] we chose N ‐propargyl‐C‐2‐substituted‐pyrroles as the starting material, synthesized as described in our previous report [16a–e] . Reaction of 13a with a base provided the indolizine derivative 15a in relatively good yield beside the allene 16 and the hydrolysis compound 17 .…”

Section: Resultsmentioning

confidence: 99%

Synthesis of Indolizines by Dimerization of N‐Propargylated Pyrroles via Allene Intermediates

et al. 2021

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Ten different N‐propargyl pyrrole derivatives having various substituents at the C‐2 position were synthesized. These derivatives were converted into indolizine derivatives by the [2+2] cycloaddition reaction of pyrrole N‐allene, forming in situ, by heating in PrOH in basic medium. The structures were characterized by NMR and X‐ray crystallography. The N‐propargylated derivatives smoothly underwent intermolecular cyclizations to produce indolizine derivatives in good yields. We proposed a radical mechanism for the dimerization. Reaction of an allene product with butylated hydroxytoluene (BHT), a radical scavenger, did not give any dimerization product. This result supports the radical reaction.

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Section: Resultsmentioning

confidence: 99%

Synthesis of Indolizines by Dimerization of N‐Propargylated Pyrroles via Allene Intermediates

et al. 2021

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“…To initiate our work, we first prepared quantitatively the corresponding 6‐bromo‐3‐fluoro‐2‐pyridinaldoxime 2 upon treatment with hydroxylamine hydrochloride in EtOH in the presence of CH 3 CO 2 Na under reflux conditions (See Supporting Information) ,. [18a] In such conditions the proton NMR of 2 revealed that the ( E )‐aldoxime was obtained stereoselectively, no trace of the ( Z )‐oxime was observed. [18b] We then used conditions to promote the Sonogashira coupling of 6‐bromo‐3‐fluoro‐2‐pyridinaldoxime 2 with 5‐phenyl‐1‐pentyne 1a as model substrate (Figure ) .…”

Section: Resultsmentioning

confidence: 99%

“…[18a] In such conditions the proton NMR of 2 revealed that the ( E )‐aldoxime was obtained stereoselectively, no trace of the ( Z )‐oxime was observed. [18b] We then used conditions to promote the Sonogashira coupling of 6‐bromo‐3‐fluoro‐2‐pyridinaldoxime 2 with 5‐phenyl‐1‐pentyne 1a as model substrate (Figure ) . We were concerned whether the 3‐fluoro group might inductively react under palladium catalysis, since electron‐deficient fluoroarenes are known to participate in palladium‐catalyzed cross‐coupling reactions,[9a], , and whether the oxime would be compatible.…”

Section: Resultsmentioning

confidence: 99%

Sonogashira Reaction of Bromofluoropyridinaldoxime Nuclei: Convergent Synthesis of Functionalized 2‐ and 3‐Fluoropyridine Scaffolds

Yerri

Baati

2018

Eur J Org Chem

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A chemoselective palladium catalyzed Sonogashira cross‐coupling of bromofluoropyridinaldoxime with highly functionalized alkynes is presented. This reaction is fully compatible with unprotected sensitive aldoxime and affords representative underexplored new scaffolds. The process exhibits a broad scope of alkynes, dialkynes, and large functional group compatibility, including the use of non‐radioactive isotopic reporter such as 15N labeled oxime and chiral substrates.

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“…[ Ru]Cl ([Ru] = Cp(PPh 3 ) 2 Ru), [23] 1a-c, [24] and 15-D 2 [25] were prepared by following methods reported in the literature.…”

Section: Generalproceduresmentioning

confidence: 99%

Reactions of a Ruthenium Complex with Substituted N‐Propargyl Pyrroles

Chia

Huang

Liu

et al. 2016

Chemistry An Asian Journal

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In an investigation into the chemical reactions of N-propargyl pyrroles 1 a-c, containing aldehyde, keto, and ester groups on the pyrrole ring, with [Ru]-Cl ([Ru]=Cp(PPh3 )2 Ru; Cp=C5 H5 ), an aldehyde group in the pyrrole ring is found to play a crucial role in stimulating the cyclization reaction. The reaction of 1 a, containing an aldehyde group, with [Ru]-Cl in the presence of NH4 PF6 yields the vinylidene complex 2 a, which further reacts with allyl amine to give the carbene complex 6 a with a pyrrolizine group. However, if 1 a is first reacted with allyl amine to yield the iminenyne 8 a, then the reaction of 8 a with [Ru]-Cl in the presence of NH4 PF6 yields the ruthenium complex 9 a, containing a cationic pyrrolopyrazinium group, which has been fully characterized by XRD analysis. These results can be adequately explained by coordination of the triple bond of the propargyl group to the ruthenium metal center first, followed by two processes, that is, formation of a vinylidene intermediate or direct nucleophilic attack. Additionally, the deprotonation of 2 a by R4 NOH yields the neutral acetylide complex 3 a. In the presence of NH4 PF6 , the attempted alkylation of 3 a resulted in the formation the Fischer-type amino-carbene complex 5 a as a result of the presence of NH3, which served as a nucleophile. With KPF6, the alkylation of 3 a with ethyl and benzyl bromoacetates afforded the disubstituted vinylidene complexes 10 a and 11 a, containing ester groups, which underwent deprotonation reactions to give the furyl complexes 12 a and 13 a, respectively. For 13 a, containing an O-benzyl group, subsequent 1,3-migration of the benzyl group was observed to yield product 14 a with a lactone unit. Similar reactivity was not observed for the corresponding N-propargyl pyrroles 1 b and 1 c, which contained keto and ester groups, respectively, on the pyrrole ring.

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Gold-Catalyzed Oxime–Oxime Rearrangement

Cited by 43 publications

References 67 publications

Synthesis of Indolizines by Dimerization of N‐Propargylated Pyrroles via Allene Intermediates

Synthesis of Indolizines by Dimerization of N‐Propargylated Pyrroles via Allene Intermediates

Sonogashira Reaction of Bromofluoropyridinaldoxime Nuclei: Convergent Synthesis of Functionalized 2‐ and 3‐Fluoropyridine Scaffolds

Reactions of a Ruthenium Complex with Substituted N‐Propargyl Pyrroles

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