1290637-87-4Relevant academic research and scientific papers
An Alternative Approach to PEPPSI Catalysts: From Palladium Isonitriles to Highly Active Unsymmetrically Substituted PEPPSI Catalysts
Zeiler, Anna,Rudolph, Matthias,Rominger, Frank,Hashmi, A. Stephen K.
, p. 11065 - 11071 (2015)
A series of new pyridine-enhanced precatalyst preparation, stabilization, and initiation (PEPPSI)-type complexes bearing different types of carbene ligands was prepared by the modular and convergent template synthesis strategy. Nitrogen acyclic carbenes, saturated and unsaturated five-membered NHC, saturated six-membered NHCs, and five-membered N-heterocyclic oxo-carbene (NHOC) ligands on palladium were prepared this way. These new organometallic compounds then were tested in Suzuki and Negishi cross-coupling reactions by using substrates with one or two substituents in ortho-position of the new C- C bond being formed. Both aryl chlorides and bromides were tested as coupling partners. In some cases, the new ligands gave results similar to Organ's successful IPr-based and IPent-based PEPPSI derivatives, with aryl bromides 0.05 mol % catalyst load still gave satisfactory results, with aryl chlorides 0.5 mol % were needed.
