Pd-catalyzed Suzuki Cross-coupling Research Articles

Simple and efficient protocol for catalyst recycling and product recovery in the Pd-catalyzed homogeneous Suzuki reaction

Poly(ethylene oxide) (PEO)/methanol can be used as solvent medium for the Pd-catalyzed Suzuki cross-coupling reaction under mild conditions. After the end of the reaction the product is extracted with heptane and the polar phase can be reused several times without any change in the activity. Pure biaryl products are obtained from the nonpolar phase in excellent isolated yields (>90%). The same catalyst-containing polar phase was used to coupling different aryl halides furnishing the biaryl products in good to high isolated yields.

A novel class of bidentate ligands with a conformationally flexible biphenyl unit built into a planar chiral [2.2]paracyclophane backbone

We report the synthesis of a novel class of planar chiral bidentate aryl[2.2]paracyclophane ligands. For the first time in the [2.2]paracyclophanyl series the Pd-catalyzed Suzuki cross-coupling was employed for the formation of the arylparacyclophanyl skeleton. From the two possible approaches: (a) cross-coupling of [2.2]paracyalophanylboronic acids with aryl halides; (b) cross-coupling of [2.2]paracyclophanyl halides with arylboronic acids, the latter was found to be more efficient. This approach was successfully used for the synthesis of a wide range of aryl[2.2]paracyclophanes with different types of substitution patterns ( ortho-, pseudo- ortho- or pseudo- gem-arrangement of the functionally-substituted aryl fragment with respect to the substituent in the paracyclophane ring).

Development of a Tripeptide Mimetic Strategy for the Inhibition of Protein Farnesyltransferase

This paper describes the development of a novel terphenyl-based tripeptide mimetic of the CAAX carboxy terminal sequence of Ras. We employ a concise synthesis to form a series of differently functionalized terphenyl inhibitors of protein farnesyltransferase (PFTase), exemplified by 5, 6 and 7. The key reaction in the synthesis of the terphenyl methyl ester 13, and therefore 6 and 7, was the Pd-catalyzed chemoselective Suzuki cross-coupling of 3-bromo-4-chloronitrobenzene 16 with an appropriate boronic acid derivative utilizing a commercially available, electron rich phosphine ligand. We further show that one member of this series is a potent inhibitor of PFTase.