Trapping of 1,2-benzo-1,3,4-cycloheptatriene as evidence for a strained cyclic allene structure

Citation
Yk. Yildiz et al., Trapping of 1,2-benzo-1,3,4-cycloheptatriene as evidence for a strained cyclic allene structure, TETRAHEDRON, 55(30), 1999, pp. 9317-9324
Citations number
26
Categorie Soggetti
Chemistry & Analysis","Organic Chemistry/Polymer Science
Journal title
TETRAHEDRON
ISSN journal
00404020 → ACNP
Volume
55
Issue
30
Year of publication
1999
Pages
9317 - 9324
Database
ISI
SICI code
0040-4020(19990723)55:30<9317:TO1AEF>2.0.ZU;2-O
Abstract
8-brom-6,7-dihydrobenzocycloheptene 16 and 9-bromo-6,7-benzocycloheptadiene 17 have been synthesized via a new and simple method, and their allene rea ctions were studied. Treatment of 16 with a base in the presence of DPIBF ( diphenylisobenzofuran) gave the strained bicyclic allene 9, which underwent a cycloaddition reaction to yield 25 and 26. On the other hand, the reacti on of the vinyl bromide 17 with a base, either in the presence or absence o f DPIBF, resulted in the formation of 7H-benzocycloheptadiene 21, rather th an the alkyne 22. (C) 1999 Elsevier Science Ltd. All rights reserved.