ISSN:
0009-2940
Keywords:
Tellurium ylides
;
Diorganyltelluronium 4,5-dicyanoimidazole-2-ylides, stability of, reactivity of, Stevens rearrangement
;
Imidazole, 2-(methyltelluro)-
;
Imidazolide, 2-(methyltelluronio)-
;
Chemistry
;
Inorganic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Stable Tellurium Ylides: Synthesis and Reactivity of Diorganyltelluronium 4,5-Dicyanoimidazol-2-ylidesDiorganyl tellurides R2Te (R=Me, Me3SiCH2, Ph) react with 2-diazo-4,5-dicyano-2H-imidazole (1) at - 30°C to form the title compounds 2 - 4. The ylides 3 and 4 are thermally stable up to their melting points of 159 and 243°C, resp., whereas 2 undergoes a modified Stevens rearrangement at 190°C with formation of a 2-(methyltelluro)imidazole (10). The reactivity of 2 - 4 is determined by an extreme charge separation between the onium centre and the ylide entity. No Wittig reactivity is observed, alkylation occurs at the imidazole nitrogen and carbanions lead to tetraorganyl tellurium compounds with limited stability.
Additional Material:
2 Tab.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/cber.19911240405
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