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Dihydroazulene/Vinylheptafulvene Photoswitch: Ultrafast Back Reaction Induced by Dihydronaphthalene Annulation
Author(s) -
Broman Søren Lindbæk,
Kushnir Oleg,
Rosenberg Martin,
Kadziola Anders,
Daub Joerg,
Nielsen Mogens Brøndsted
Publication year - 2015
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.201500320
Subject(s) - chemistry , photoswitch , annulation , cyclohexane , stereochemistry , photoisomerization , photochemistry , combinatorial chemistry , organic chemistry , isomerization , catalysis
The vinylheptafulvene (VHF) to dihydroazulene (DHA) electrocyclization is known to proceed from an s‐ cis conformation of VHF and cannot occur from the more stable s‐ trans conformation. Locking the VHF in the s‐ cis conformation by the introduction of a dihydronaphthalene (DHN) unit has been found to greatly enhance the speed of this reaction. Thus, the half‐life was reduced by more than a factor of 150000 in cyclohexane and by a factor of approximately 950000 in ethanol. In addition, the characteristic absorption of the photoactive DHA isomer, now annulated to DHN, exhibited a desired redshift relative to the parent compound. Here, we present the synthesis and study of these DHN‐DHA/VHFs, including a protocol for the incorporation of a pseudo‐halide to enable the further functionalization of the molecule by metal‐catalyzed cross‐coupling reactions. For proof‐of‐concept, two different sulfur end‐groups were incorporated as anchoring groups for potential molecular electronics applications.