UCLA

The effect of pi ligands, 3-hexyne and 1,2-cyclononadiene, in the Chan-Lam modification of the Ullmann reaction was investigated. Reaction conditions were optimized to give the highest yields in this copper(II) mediated oxidative coupling of boronic acids and arylamines. Pyridine proved to be a more efficient base than triethylamine for the substrates screened. It was found that 3-hexyne and 1,2-cyclononadiene had a beneficial effect on most of the substrates screened. The yields ranged from modest to excellent. A small self-ligating effect from olefin-substituted phenyl boronic acids was observed.