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Equilibrium Study of Pd(dba)₂ and P(OPh)₃ in the Pd-Catalyzed Allylation of Aniline by Allyl Alcohol.

ABSTRACT: 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-P distance of 2.25 Å due to the π-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 π-allyl-Pd[P(OPh)₃]₂ intermediate according to ESI-MS studies.

SUBMITTER: Sawadjoon S

PROVIDER: S-EPMC3893935 | biostudies-literature |

REPOSITORIES: biostudies-literature

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