[2+2] Photodimerization of bispyridylethylenes by a controlled shift of the protonation equilibrium

Irradiation of trans-4,4′-bispyridylethylene in the presence of 1equiv of concd HCl produced a syn dimer with high selectivity, whereas irradiation in the presence of more than 2equiv of concd HCl or in the absence of HCl gave a mixture of dimers and by-products with much lower selectivity. This ind...

Full description

Saved in:
Bibliographic Details
Published inTetrahedron letters Vol. 54; no. 30; pp. 3997 - 4000
Main Authors Yamada, Shinji, Kusafuka, Momoko, Sugawara, Mai
Format Journal Article
LanguageEnglish
Published OXFORD Elsevier Ltd 24.07.2013
Elsevier
Subjects
[2+2] Photodimerization
Bispyridylethylene
Byproducts
Catalysis
Cations
Cation–π interaction
Chemistry
Chemistry, Organic
Dimers
Irradiation
Physical Sciences
Protonation
Pyridines
Science & Technology
Selectivity
Stereoselective reaction
Tetrahedrons
[2+2] Photodimerization
Cation–π interaction
Catalysis
Bispyridylethylene
Stereoselective reaction
TRANSFORMATION
COMPLEX
ISOMERIZATION
REACTIVITY
SOLID-STATE
PHOTOREACTIONS
CYCLOADDITION
Cation-pi interaction
AZASTILBENES
STILBAZOLES
TEMPLATE
Online AccessGet full text

Cover

More Information
Summary:Irradiation of trans-4,4′-bispyridylethylene in the presence of 1equiv of concd HCl produced a syn dimer with high selectivity, whereas irradiation in the presence of more than 2equiv of concd HCl or in the absence of HCl gave a mixture of dimers and by-products with much lower selectivity. This indicated that a suitable amount of acid served as a catalyst for the [2+2] photodimerization of BPEs through cation–π interactions between the pyridinium and pyridine rings.
Bibliography:ObjectType-Article-1
SourceType-Scholarly Journals-1
ObjectType-Feature-2
content type line 23
ISSN:0040-4039
1873-3581
DOI:10.1016/j.tetlet.2013.05.075