A convenient synthesis of symmetric 1,2-diarylethenes from arylmethyl phosphonium salts.
Symmetric ethenyldithiophenes are important intermediates for synthesis of photochromic materials and organic conductors. When acetonitrile is used as a solvent, 3-methylthiophenylphosphonium salts form symmetric ethenyldithiophenes in the presence of a strong base (e.g., NaH, (t)BuOK) in moderate to high yields. This homocoupling reaction is faster than a Wittig reaction with aromatic ketones in acetonitrile. Our study shows that the presence of polar aprotic solvents promotes the homocoupling reaction.
Ngwendson
Julius N
JN
Department of Chemistry, University of North Dakota, Grand Forks, ND 58202-9024, USA.
Atemnkeng
Walters N
WN
Schultze
Cassandra M
CM
Banerjee
Anamitro
A