ISSN:
0018-019X
Keywords:
Chemistry
;
Organic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Reactions of Fischer Carbene Complexes of 1,6-Methano[10]annuleneThe new Fischer carbene complexes 7, 8, and 10 of 1,6-methano[10]annulene as well as the bis(carbene) complex 15, were readily available in moderate yields by using the classical Fischer method (Schemes 1 and 2). The complexes 5 and 7 reacted easily with several alkynes under benzo-annulation conditions (Dötz reaction). Depending on the workup conditions, the new benzoquinones 16 and 17 (Scheme 5), hydroquinones 19 and 20 (Scheme 6), and protected hydroquinones 23-25 (Schemes 6 and 7) were synthesized. Surprisingly, in one run we were able to isolate the air-stable [Cr(η6-arene)(CO)3] complex 26 (Scheme 7). The X-ray structure and NMR data of 26 established a remarkable perturbation of the 10π perimeter of the 1,6-methano[10]annulene part in the hydroquinones 19-26, but no evidence of a σ-homoaromatic “bis(trinorcaradiene)” system. The first double Dötz reaction of 15 with hex-3-yne resulted in the formation of the “anti”-dibenzo-annulated 1,6-methano[10]annulene 32 (Scheme 8), which does not exist furthermore as a π-homoaromatic system, but as its σ-homoaromatic valence isomer.
Additional Material:
1 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/hlca.19940770818
Permalink
