Abstract The tetraphosphine cis, cis, cis-1, 2, 3, 4-tetrakis (diphenylphosphinomethyl) cyclopentane in combination with [Pd (C 3 H 5) Cl] 2 affords a very efficient catalyst for the alkynylation of ortho-substituted aryl bromides. A wide variety of substituents such as phenyl, trifluoromethyl, acetyl, formyl or nitrile, are tolerated. High turnover numbers can be obtained with most of these aryl bromides. The coupling of sterically very congested aryl bromides ...
