Farina, V.; Krishnan, B. J. Am. Chem. Soc. 1991, 113, 9585-9595.
In the article, “Large Rate Accelerations in the Stille Reaction with Tri-2-furylphosphine
and Triphenylarsine as Palladium Ligands: Mechanistic and Synthetic Implications”,
Vittorio Farina and Bala Krishnan studied the effect of different palladium ligands on the
rates of Stille cross-coupling reactions. Transmetalation is the rate-determining step in
the catalytic cycle of Stille coupling reactions and involves the formation of a pi-complex
between the metal and the double bond in the stannane. Therefore, ligands that are most
efficient at dissociating from the Pd(II) and allow for the formation of this pi-complex
yield the fastest coupling rates. Farina and Krishnan found that using tri-2-furylphosphine
(TFP) and triphenylarsine resulted in great rate enhancements in the coupling reaction—
around 102 to 103 greater than when triphenylphosphine-based catalysts were used. As
a result, from their studies, TFP and triphenylarsine have been proposed to be the most
appropriate ligands to use in palladium-catalyzed coupling between olefinic stannanes and
electrophiles.
This article describes a synthesis using Pd-catalyzed cross-coupling methods. It
refers to a ligand researched in Farina’s article, TFP. It states that isomerization
of the double bond in allyl stannanes can be prevented when using tri(2-
furyl) phosphine, TFP, as the palladium ligand in Stille cross-couplings.
Articles with this citation:
Samaritani, S.; Signore, G.; Malanga, C.; Menicagli, R. Tetrahedron. 2005, 61, 4475-4483.
This article describes a synthesis using Pd-catalyzed cross-coupling methods. It refers to a
ligand researched in Farina’s article, TFP. It states that isomerization of the double bond in
allyl stannanes can be prevented when using tri(2-furyl) phosphine, TFP, as the palladium
ligand in Stille cross-couplings.
This article referenced Farina’s article when describing an sp3-sp2 Stille coupling with a
vinylstannane to synthesize the desired compound. The catalyst used was made up of 5
mol% Pd2(dba)3 and 20 mol% tris(2-fury)phosphine, also known as TFP, which was the
ligand studied in Farina’s article. This catalyst gave the best results in the coupling process
amongst many other catalysts, solvents, and additives, which was stated to have shown no
significant improvements in the yield of the product.
Lee, H. B.; Huh, D H.; Oh, J. S.; Min, G. H.; Kim, B. H.; Lee, D. H.; Hwang, J. K.; Kim, Y. G.
Tetrahedron. 2001, 57, 8283-8290.
This article referenced Farina’s article when testing different phosphine ligands for the
optimal conditions in producing the desired products. The ligands were tested with 10
mol% of PdCl2(PPh3)2 in benzene or with 10 mol% of Pd2(dba)3 in DMF, both at room
temperature. The Tri-2-furylphosphine (TFP), which was studied in Farina’s article, and
PPh3 were efficient in both solvents at improving the coupling reactions, while other
ligands such as dppb and P(p-MeOPh)3 were not as effective.
