ISSN:
0009-2940
Keywords:
Magnesium anthracene
;
Grignard compounds
;
Magnesium, active
;
Radical transfer reaction
;
Allenylmagnesium chloride
;
Chemistry
;
Inorganic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The course (a), (b), (c) (Scheme 1) of the reaction of magnesium anthracene·3THF (1) with organic halides (RX) is dependent on the nature of RX. With alkyl halides in THF 1 reacts as a nucleophile, whereby primary as well as secondary alkyl halides produce dialkyldihydroanthracenes (4-4′′) and tertiary alkyl halides yield primarily monoalkyl-substituted dihydroanthracenes (2, 2′). With bromo- and iodobenzene in THF 1 reacts predominantly as a radical with H atom abstraction from the solvent affording benzene and 9. The formation of Grignard compounds (5) and anthracene (6), originating from primary and secondary alkyl and aryl halides and 1 in toluene or ether at elevated temperatures, is not caused by the reaction of 1 but by the “active magnesium” (Mg*) formed by decomposition of 1 in these solvents. In contrast, allyl, propargyl, and benzyl halides react with 1 independently of the solvent under mild conditions to produce 5 and 6. Allyl- and the difficultly accessible allenylmagnesium chloride can be prepared in THF at -78 and 0°C, respectively, from the corresponding halides and ordinary Mg powder via catalytic amounts of 1.
Additional Material:
5 Tab.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/cber.19901230711
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