Eighty-two years after the discovery by Bertholet in 1866 that acetylene thermally trimerizes to benzene in low yield at temperatures in excess of 400 C, 1 Reppe reported that this reaction is catalyzed near room temperature in solutions of nickel complexes. 2 Since then, alkyne trimerization has become one of the most intensely studied synthetically useful transformations, and many transition-metal systems including salts, oxides, organometallic ...
