ISSN:
1434-193X
Keywords:
Chromium
;
Benzocyclobutene
;
Dianionic Oxy-Cope Rearrangement
;
Methoxyallene
;
Benzocycloheptenedione
;
Chemistry
;
General Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Addition of carbon nucleophiles to (benzocyclobutenedione)tricarbonylchromium(0) (4) results in the formation of exo mono- and diadducts as well as 1,2-diketones as the consequence of proximal ring-opening reactions. In one case the unexpected formation of benzocycloheptenedione complexes is observed. Treatment of 4 with an excess of 1-ethoxy-1-lithioethene gives the product of a dianionic oxy-Cope rearrangement followed by an intramolecular aldol addition. This is also the case with lithiated methoxyallene, and as the result the first head-to-head coupling product 12 of two methoxyallene molecules is isolated in good yield. 12 is used as a diene in Diels-Alder cycloadditions, and its molecular structure is compared to that of the similar molecule 13, lacking the two exo methylene substitutents.
Additional Material:
2 Ill.
Type of Medium:
Electronic Resource
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