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Protonation‐Induced Cyclocondensation of 1‐Aryl Ethynylanthraquinones: Expanding the π Conjugation
Author(s) -
Kondo Mio,
Uchikawa Maai,
Zhang WenWei,
Namiki Kosuke,
Kume Shoko,
Murata Masaki,
Kobayashi Yoshio,
Nishihara Hiroshi
Publication year - 2007
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.200701766
Subject(s) - intramolecular force , protonation , aryl , chemistry , electron transfer , derivative (finance) , proton , combinatorial chemistry , stereochemistry , photochemistry , organic chemistry , physics , nuclear physics , ion , alkyl , financial economics , economics
Just add a proton : The cyclocondensation of 1‐aryl ethynylanthraquinones in the presence of a strong organic acid proceeds almost quantitatively to give oxodihydrodibenzochromenylium compounds (see scheme for a 1‐ferrocenyl derivative; blue C, red O, purple Fe). Expansion of the π‐conjugated system of the starting anthraquinones causes a lowering of the π* orbital and promotes intramolecular electron transfer.