Stable but chimeric antiaromatic 1H-azirines? A threefold reinvestigation

Banert, Klaus; Bochmann, Sandra; Hagedorn, Manfred; Richter, Frank

doi:10.1016/j.tetlet.2013.08.122

Cited by 7 publications

(2 citation statements)

References 72 publications

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“…1 H -Azirine ring systems are antiaromatic with high ring strain and high reactivity . For this reason, they are very unstable and, as has been recently demonstrated by Prof. Banert et al, 1 H -azirines “are very short lived intermediates, which can be detected only at very low temperature with the help of the noble gas matrix isolation technique”, although they are reported as very short-lived intermediates in the formation of nitrogen heterocycles …”

Section: Resultsmentioning

confidence: 99%

Reaction of 2H-Azirine-Phosphine Oxides and -Phosphonates with Enolates Derived from β-Keto Esters

et al. 2015

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Cyclopenta[b]-pyrrole-2-phosphine oxides 4a and -phosphonates 4b,c are generated by the addition of cyclic enolates derived from ethyl 2-oxo-cyclopentanecarboxylate 2 to phosphorated 2H-azirines 1. However, the addition of enolate derived from acyclic 2-oxo-butanoate 10 to 2H-azirine phosphine oxide 1 led to vinylogous N-acyl-α-aminoalkyl phosphine oxides 12, involving the carbonyl group and the Cα of the keto ester 10. Ring closure of vinylogous derivative 12 in the presence of base afforded pyrrole-2-phosphine oxide 11. The addition of enolates derived from indenone-carboxylate 15 to 2H-azirines 1 led to the formation of functionalized N-substituted 1H-benzo[d]azepine derivatives 17.

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Section: Resultsmentioning

confidence: 99%

Reaction of 2H-Azirine-Phosphine Oxides and -Phosphonates with Enolates Derived from β-Keto Esters

et al. 2015

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“…Etheral solutions of cumulene 2 were later found to ensure safe handling, but not without minimal self-heating, as sign of slow polymerization. On treatment with nucleophiles (NuH), solutions of 2 lead to thiazoles of type 3 , and several similar heterocyclic products can be prepared with high yields by the reactions of 2 in one-pot procedures. − …”

Section: Introductionmentioning

confidence: 99%

Chemical Safety Note: Explosion Hazard during the Distillation of Propargyl Thiocyanate

Banert

Richter

Hagedorn

2015

Org. Process Res. Dev.

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This study is based on the efforts to understand the cause of a laboratory accident at a university in Germany. An explosion occurred during the distillation of propargyl thiocyanate(1), a well-known compound. It is assumed, that an unwanted [3,3]-sigmatropic rearrangment under thermal conditions led to the accumulation of highly reactive isothiocyanatopropa-1,2-diene (2), which actually was the explosive substance. To assess the hazard potential of the established purification procedure, pure 1 was analyzed by DTA and 2 by isothermal reaction calorimetry. The results support our hypothesis of unintended formation of dangerous 2, and safety advice is given to prevent future incidents.

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Indoles from Alkynes and Aryl Azides: Scope and Theoretical Assessment of Ruthenium Porphyrin‐Catalyzed Reactions

Intrieri

Carminati

Zardi

et al. 2019

Chemistry A European J

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As ymbiotic experimental/computational study analyzed the Ru(TPP)(NAr) 2 -catalyzed one-pot formation of indoles from alkynes and aryl azides. Thirty different C 3 -substituted indoles were synthesized and the bestp erformance, in term of yields and regioselectivities, was observed when reacting ArCCH alkynes with 3,5-(EWG) 2 C 6 H 3 N 3 azides, whereas the reaction was less efficient when using electron-rich aryl azides. AD FT analysisd escribes the reaction mechanism in terms of the energy costs and orbital/electronic evolutions;t he limitedr eactivity of electron-rich azides was also justified.I ns ummary,P hCCH alkyne interacts with one NAr imido ligand of Ru(TPP)(NAr) 2 to give ar esidually dangling C(Ph) group, which, by coupling with aC (H) unit of the Naryl substituent, forms a5+ 6b icyclic molecule.I nt he process, two subsequent spin changes allow inverting the conformation of the sp 2 C(Ph) atom and its consequente lectrophilic-like attack to the aromatic ring. The bicycle isomerizes to indole via at wo-step outer sphere H-migration. Eventually,a'Ru(TPP)(NAr)' mono-imidoa ctive catalyst is reformed after each azide/alkyne reaction.[a] Dr.

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Stable but chimeric antiaromatic 1H-azirines? A threefold reinvestigation

Cited by 7 publications

References 72 publications

Reaction of 2H-Azirine-Phosphine Oxides and -Phosphonates with Enolates Derived from β-Keto Esters

Reaction of 2H-Azirine-Phosphine Oxides and -Phosphonates with Enolates Derived from β-Keto Esters

Chemical Safety Note: Explosion Hazard during the Distillation of Propargyl Thiocyanate

Indoles from Alkynes and Aryl Azides: Scope and Theoretical Assessment of Ruthenium Porphyrin‐Catalyzed Reactions

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