Green Palladium(II) Catalysis
- Status
- New Project
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- Background
- Research by R. F. Heck and T. Mizoroki in the early 1970s led to the discovery of the palladium(0)-catalyzed vinylic substitution reaction, nowadays commonly called the Heck reaction. This highly versatile and useful carbon-carbon bond forming methodology using organo halides (or pseudohalides) as substrates has gained much interest over the years and is today a frequently employed synthetic tool. The palladium(II)-mediated version using organoboronic acids as arylmetal precursors did not cause much attention until the first catalytic protocols were reported by Uemura, Du and Jung. In 2004 we introduced the first ligand-modulated oxidative Heck reaction employing 2,9-dimethyl-1,10-phenanthroline (dmphen) to facilitate palladium reoxidation, to increase catalytic stability and to control the regioselectivity with electron-rich olefins. With dmphen, palladium loadings could be reduced and atmospheric air could be used as the sole reoxidant.
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- Aim
- To develop new, green oxidative Heck reaction protocols, employing air for the essential Pd(II) recycling. To explore the scoop of the reaction in medicinal chemistry projects. To use the Pd(II)-dmphen system also for other classes of coupling reactions.
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- Method
- We are directing our research work towards chiral oxidative Heck couplings, enabling stereoselective generation of both tertiary and quaternary carbon centers from arylboronic acids. We investigate and expand the usefulness of intramolecular oxidative Heck reactions for synthesis of rigidified structures. Moreover, we are examining the unique capacity of the Pd(II)-dmphen catalyst to produce arylpalladium(II) intermediates from arylboronic acids at room temperature. Thus, we hope to develop new types of C-C bond forming coupling reactions.
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Last modified at 2008-08-12 10:56 by Sorin Srbu
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