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A Novel Route to a Bromo‐Cyano‐Substituted Azulene and Its Exploitation in the Construction of an Acetylenic Scaffold
Author(s) -
Petersen Michael Åxman,
Kilså Kristine,
Kadziola Anders,
Nielsen Mogens Brøndsted
Publication year - 2007
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.200601052
Subject(s) - azulene , chemistry , halogenation , oxidative coupling of methane , dimer , palladium , bromide , block (permutation group theory) , medicinal chemistry , combinatorial chemistry , catalysis , organic chemistry , geometry , mathematics
A novel route to functionalized azulenes is devised from a dihydroazulene precursor. Thus, bromination of 1,1‐dicyano‐2‐phenyl‐1,8a‐dihydroazulene followed by heating in the presence of bromide ions provides an efficient way to generate 3‐bromo‐1‐cyano‐2‐phenylazulene. Formation of this somewhat unexpected product was confirmed by X‐ray crystallographic analysis. It undergoes a palladium‐catalyzed cross‐coupling reaction with trimethylsilylacetylene, affording a new azulene building block for acetylenic scaffolding. Oxidative homo‐coupling hereof provides an azulene dimer, for which the optical and electrochemical properties are compared to the other azulenes. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)