Notiz zur Umsetzung von 3,4‐Diphenyl‐1,2‐cyclobutendion mit Grignard‐Verbindungen

Hambrecht, Jürgen; Straub, Henner; Müller, Eugen

doi:10.1002/cber.19741071228

Cited by 10 publications

(2 citation statements)

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“…3‐Ethyl‐1,2,4‐trimethylcyclobut‐3‐ene‐1,2‐diol (14 j) and 3,4‐diethyl‐1,2‐dimethylcyclobut‐3‐ene‐1,2‐diol (14 k) : Treatment of 3‐ethyl‐4‐methylcyclobut‐3‐ene‐1,2‐dione ( 13 j=13 k′ ) or 3,4‐diethylcyclobut‐3‐ene‐1,2‐dione ( 13 h = 13 k ) with methylmagnesium bromide was carried out analogously to a known procedure21b to get 14 j and 14 k , respectively.…”

Section: Methodsmentioning

confidence: 99%

Experimental and Theoretical Characterization of the Valence Isomerization of Bi‐2H‐azirin‐2‐yls to Diazabenzenes

Banert

Herges

Heß

et al. 2006

Chemistry A European J

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3,4-diazidocyclobutenes 16 were prepared from the corresponding dihalides. Some of these diazides, such as parent compound 16 d and phenyl-substituted derivatives 16 c,f, underwent spontaneous stereoselective electrocyclic ring opening below room temperature, whereas the tetraalkyl derivatives of 16 had to be heated to force the same reaction. In most cases, the resulting 1,4-diazidobuta-1,3-dienes 8 were isolated to study their photochemical transformation into bi-2H-azirin-2-yls 9 via intermediate mono-azirines 17. Except for starting materials with a low number of substituents such as 9 d and 9 f, title compounds 9 underwent a thermal valence isomerization which led exclusively to pyridazines 18 at surprisingly low temperatures. Based on quantum-chemical calculations for the parent bi-2H-azirinyl-2-yl 9 d at the UB3LYP/6-31+G(d) and MR-MP2/TZV(2df,2p) levels, the valence isomerization process is best explained by simultaneous homolytic cleavage of both C--N single bonds of 9 to generate energetically favorable N,N' diradicals 26, which cyclize to 18. The theoretical studies indicate also that one stereoisomer of 9, namely, the rac compound, should undergo valence isomerization more easily than the other, which is in conformity with different rates of these rearrangement reactions found experimentally. For the tetramethyl-bi-2H-azirin-2-yls 9 g, which are better models for the experimentally studied compounds, simultaneous homolytic cleavage of both C--N single bonds is also predicted by the calculations, although the intermediate diradicals 26 g are significantly higher in energy than those of the parent system 9 d.

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Section: Methodsmentioning

confidence: 99%

Experimental and Theoretical Characterization of the Valence Isomerization of Bi‐2H‐azirin‐2‐yls to Diazabenzenes

Banert

Herges

Heß

et al. 2006

Chemistry A European J

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“…Und mehr denn je muss jeder nach Abschluss seiner Ausbildung damit rechnen, mindestens einmal auf seinem weiteren Lebensweg eine völlig neue, mit dem ursprünglich erlernten Gebiet nicht verwandte Qualifikation erwerben zu müssen. Das galt und gilt auch für meinen eigenen Berufsweg: Mein Forscherinteresse galt zunächst den polymeren Nebenprodukten bei den niedermolekularen organischen Synthesen 2. Meine wissenschaftliche Neugier führte mich über das Thema meiner Doktorarbeit beim Eintritt in die BASF direkt in die Polymerchemie.…”

Section: Vernetzt Denken Lebenslang Lernenunclassified

Zukunft gestalten mit Chemie: Was junge Chemiker in Forschung und Unternehmen erwartet

Hambrecht¹

2006

Angewandte Chemie

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Shaping the Future with Chemistry: What's in Store for Chemistry Graduates in Research and Industry?

Hambrecht¹

2006

Angew Chem Int Ed

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Notiz zur Umsetzung von 3,4‐Diphenyl‐1,2‐cyclobutendion mit Grignard‐Verbindungen

Abstract: Eingegangen a m 12. Juni 1974 3,4-Diphenyl-1,2-cyclobutendion 1) (1) zeigt mit Grignard-Reagenzien ein unterschiedliches Reaktionsverhalten : Ried und Lanfzsch erhielten aus 1 und Arylmagnesiumbromiden cis-

Cited by 10 publications

References 9 publications

Experimental and Theoretical Characterization of the Valence Isomerization of Bi‐2H‐azirin‐2‐yls to Diazabenzenes

Experimental and Theoretical Characterization of the Valence Isomerization of Bi‐2H‐azirin‐2‐yls to Diazabenzenes

Zukunft gestalten mit Chemie: Was junge Chemiker in Forschung und Unternehmen erwartet

Shaping the Future with Chemistry: What's in Store for Chemistry Graduates in Research and Industry?

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