syn- and anti-Bishomoanthraquinone (pages 1000–1002)
Prof. Dr. Emanuel Vogel, Stefan Böhm, Dr. Achim Hedwig, Dr. Bernd O. Hergarten, Dr. Johann Lex, Dr. Joachim Uschmann and Prof. Dr. Rolf Gleiter
Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.198610001
The remarkable regio- and stereoselectivity of the bromination of syn-bismethanoannulene 1 can be explained in terms of pronounced π/σ interactions in 1. The product is almost exclusively (90%) the 7,14-dibromo derivative 2, which can be converted via solvolysis and oxidation into the syn-bishomoanthraquinone 3. With regards to its quinonoid properties, this potential building block for “bishomoanthraquinone dyes” compares with anthraquinone rather than with p-benzoquinone. For steric reasons, in the case of the anti-isomer of 3 the quinonoid character diminishes further.