Sonogashira coupling reaction with diminished homocoupling.
[reaction: see text] The side product from homocoupling reaction of two terminal acetylenes in the Sonogashira reaction can be reduced to about 2% using an atmosphere of hydrogen gas diluted with nitrogen or argon. Terminal arylethynes, diarylethynes, and a few new arylpyridylethynes with donor substituents have been synthesized in very good yields. Comparative control experiments suggest that the homocoupling yield is determined by concentration of both catalyst and oxygen.
Elangovan
Arumugasamy
A
Department of Chemistry, National Taiwan University, Taipei 106, Taiwan ROC.
Wang
Yu-Hsiang
YH
Ho
Tong-Ing
TI