Suzuki–Miyaura and Hiyama reactions catalyzed by orthopalladated triarylphosphite complexes

The Hiyama Cross-Coupling Reaction at Parts Per Million Levels of Pd: In Situ Formation of Highly Active Spirosilicates in Glycol Solvents

A palladium NNC-pincer complex at a 5 mol ppm loading efficiently catalyzed the Hiyama coupling reaction of aryl bromides with aryl(trialkoxy)silanes in propylene glycol to give the corresponding biaryls in excellent yields. This method was applied to the syntheses of adapalene and a biaryl-type liquid-crystalline compound, as well as to the derivatization of dextromethorphan and norfloxacin. ESI-MS and NMR analyses of the reaction mixture suggested the formation of pentacoordinate spirosilicate intermediates in situ. Preliminary theoretical studies revealed that the glycol-derived silicate intermediates formed in situ are quite reactive silicon reagents in the transmetalation step.

MIDA as a simple and highly efficient ligand for palladium-catalyzed Hiyama cross-coupling of aryl halides

N-Methyliminodiacetic acid (MIDA) as a simple, air stable and water-soluble ligand has been used in the palladium-catalyzed Hiyama cross-coupling reaction of trimethoxyphenylsilane with aryl halides. The yield of the corresponding Hiyama coupling products is high up to around 90% in water and isopropanol under an ambient atmosphere in the presence of KOH and NaF.

A covalently anchored 2,4,6-triallyloxy-1,3,5-triazine Pd(ii) complex over a modified surface of SBA-15: catalytic application in hydrogenation reaction

Highly efficient and reusable SBA-15–TAT–Pd(ii) has been synthesized by anchoring a 2,4,6-triallyloxy-1,3,5-triazine (TAT) complex over the organo-functionalized surface of SBA-15.