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Dihydroazulene Photoswitches: The First Synthetic Protocol for Functionalizing the Seven‐Membered Ring
Author(s) -
Petersen Michael Åxman,
Broman Søren Lindbæk,
Kadziola Anders,
Kilså Kristine,
Nielsen Mogens Brøndsted
Publication year - 2009
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.200900297
Subject(s) - regioselectivity , chemistry , photoswitch , ring (chemistry) , structural isomer , halogenation , photochromism , combinatorial chemistry , alkyne , stereochemistry , photochemistry , organic chemistry , catalysis
The first synthetic protocol for functionalizing the dihydroazulene (DHA) photoswitch in its seven‐membered ring has been developed. This protocol is based on regioselective bromination, followed by regioselective elimination of HBr, and finally a palladium‐catalyzed cross‐coupling reaction with a terminal alkyne. The position of functionalization (C‐7) was confirmed by X‐ray crystal structure analysis. Light‐induced ring opening of this compound to its vinylheptafulvene (VHF) isomer followed by thermal ring closure provides a mixture of two DHA regioisomers in a ratio that depends on the wavelength of irradiation and solvent polarity.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)