1′-Carbopalladated-4-ferrocenyl-1,3-oxazolines as catalysts for Heck reactions: Further evidence in support of the Pd(0)/Pd(II) mechanism

1′-Carbopalladated complexes derived from 4-ferrocenyl-1,3-oxazolines are reported in this paper as efficient catalysts for the Heck coupling of iodo- and bromoarenes with alkenes. Experimental evidence points out strongly towards the involvement of a Pd(0)/Pd(II) catalytic cycle in the mechanism of the reaction. For the first time, the disassembly of the carbopalladated complex via coupling with the olefin in a non-catalytic Heck reaction has been demonstrated to be the origin of the release of Pd(0) from the palladacycle carrier.

Graphical abstract1′-Carbopalladated complexes derived from 4-ferrocenyl-1,3-oxazolines behave as pre-catalysts for the Heck coupling of iodo- and bromoarenes with alkenes. The reaction proceeds through a Pd(0)/Pd(II) catalytic cycle. The release of Pd(0) from the palladacycle takes place by coupling with the olefin in a non-catalytic Heck reaction.Figure optionsDownload full-size imageDownload as PowerPoint slide