catalysis tops that of the hitherto most active molecular group 2 metal catalysts. Depending on the substrate, two different catalytic cycles are proposed. A: a classical metal hydride cycle and B: the Ba metal cycle. The latter is proposed for substrates that are easily reduced by Ba0, that is, conjugated alkenes, alkynes, annulated rings, imines and pyridines. In addition, a mechanism in which Ba0 and BaH2
Nickel-catalyzed cocyclotrimerization of arynes with diynes; a novel method for synthesis of naphthalene derivatives
作者:Jen-Chieh Hsieh、Chien-Hong Cheng
DOI:10.1039/b415691a
日期:——
The NiBr2(dppe)–Zn system effectively catalyzes the [2 + 2 + 2] cocyclotrimerization of arynes with diynes, leading to substituted naphthalene derivatives in moderate to good yields. This cocyclotrimerization reaction shows excellent tolerance of functional groups and leads to products of 5- to 7-membered fused-ring sizes