ISSN:
0009-2940
Keywords:
Single-electron transfer vs. carbonyl attack
;
Tetrahydrobianthracene, disproportionation of
;
Radical combination
;
Chemistry
;
Inorganic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Arene Hydrides, 8. - SET vs. Nucleophilic Attack in Reactions of α-Bromoisobutyrophenone with Carbanions. Fragmentation of the Anion of TetrahydrobianthraceneSET is the main reaction pathway between α-bromoisobutyrophenone (1) and the carbanions 7a-j- of diarylmethanes or disubstituted acetonitriles: 7- → 7. + e and e + 1 →→ Br- PhCOCMe.2 (3). Main secondary reactions are dimerization of the radical 7. (to form 6) and further reduction of 3: 7- + 3 → 7. + 4 [enolate of isobutyrophenone (5)]. Occasionally substitution products (9) of 1 are obtained. They are probably formed by combination of 7. with 3 (0% 9e at room temperature, 38% 9e at -65°C). This combination seems to be favored by cation coordination. In the reaction with 7f- (“anthracene hydride”) the dimer 6f (and probably 9f, too) undergoes fragmentation to form anthracene. The epoxide 16, arising from 1 by carbonyl attack, has been found only once with 7a-j-; (1% 16b). In contrast, 16 was the (elusive) main product in the reaction of 1 with the carbanions 7k-n- of monosubstituted acetonitriles. Here, 6 and 9 have been found only once (61, 9n). The elusive 16k-n underwent eliminative ring fission.
Additional Material:
2 Tab.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/cber.19901230716
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