Palladium-Catalyzed Amination of Aryl Bromides and Aryl Triflates Using Diphosphane Ligands: A Kinetic Study
✍ Scribed by Yannick Guari; Gino P. F. van Strijdonck; Maarten D. K. Boele; Joost N. H. Reek; Paul C. J. Kamer; Piet W. N. M. van Leeuwen
- Publisher
- John Wiley and Sons
- Year
- 2001
- Tongue
- English
- Weight
- 224 KB
- Volume
- 7
- Category
- Article
- ISSN
- 0947-6539
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✦ Synopsis
Pd(PÀOÀP)(Ar)] complexes with ligands that have wide bite angles are active catalysts for the coupling of aniline derivatives with aryl triflates. Kinetic studies show that for these systems a fast equilibrium that involves coordination of the amine precedes the deprotonation, which is the rate-limiting step of the reaction. This reaction is faster for compounds with a smaller P À Pd À P angle. When halide salts are present, the base sodium tert-butoxide is activated and adds to the palladium complex. This rate-limiting step is preceded by a fast equilibrium that involves decoordination of the halide. The initial reaction rate is faster for compounds with a larger PÀPdÀP angle. This is due to the closer proximity of the oxygen to the Pd center, and this assists in the dissociation of the halide.