Equilibrium Study of Pd(dba)2 and P(OPh)3 in the Pd-Catalyzed Allylation of Aniline by Allyl Alcohol
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- 作者：Supaporn Sawadjoon ; Andreas Orthaber ; Per J. R. Sj?berg ; Lars Eriksson ; Joseph S. M. Samec
- 刊名：Organometallics
- 出版年：2014
- 出版时间：January 13, 2014
- 年：2014
- 卷：33
- 期：1
- 页码：249-253
- 全文大小：252K
- ISSN：1520-6041
文摘
Reaction of Pd(dba)2 and P(OPh)3 shows a unique equilibrium where the Pd[P(OPh)3]3 complex is favored over both Pd(dba)[P(OPh)3]2 and Pd[P(OPh)3]4 complexes at room temperature. At a lower temperature, Pd[P(OPh)3]4 becomes the most abundant complex in solution. X-ray studies of Pd[P(OPh)3]3 and Pd(dba)[P(OPh)3]2 complexes show that both complexes have a trigonal geometry with a Pd鈥揚 distance of 2.25 脜 due to the 蟺-acidity of the phosphite ligand. In solution, pure Pd(dba)[P(OPh)3]2 complex equilibrates to the favored Pd[P(OPh)3]3 complex, which is the most stable complex of those studied, and also forms the most active catalytic species. This catalyst precursor dissociates one ligand to give the reactive Pd[P(OPh)3]2, which performs an oxidative addition of nonmanipulated allyl alcohol to generate the 蟺-allyl-Pd[P(OPh)3]2 intermediate according to ESI-MS studies.