18269-31-3

The synthesis of 2-pyrimidyldiphenylphosphine (2), bis-2- pyrimidylphenyl-phosphine (3) and tris-2-pyrimidylphosphine (4) is described. Ligand 2 forms cationic complexes with palladium(II) in which four-membered P/N-chelates are involved, leading to a ver

The alkoxycarbonylation of trimethylsilylacetylene has been studied in order to develop an atom economic sustainable synthesis of 2-(trimethylsilyl)acrylates, a family of valuable intermediates. Pd(OAc)2 in combination with CH3SO3H and diphenyl-(pyridin-2-yl)phosphine or diphenyl-(6-methyl-pyridin-2-yl)phosphine is an active catalyst for the reaction affording mixtures of the sought 2-(trimethylsilyl)acrylate and the isomeric 3-(trimethylsilyl)acrylate. The phosphine ligand has a dramatic effect on the reaction. When employing diphenyl-(pyridin-2-yl)phosphine, it is necessary to carry out the reaction at 80°C in order to observe a modest catalytic activity, and the product is an almost equimolecular mixture of the two isomeric esters. On the contrary, when employing diphenyl-(6-methyl-pyridin-2-yl)phosphine, the reaction proceeds under much milder conditions affording with high rate (turnover frequency [TOF] up to 1200 h?1) and selectivity (>95%) of the sought 2-(trimethylsilyl)acrylate. The reaction conditions have been optimized, and the effects of phosphine/palladium, acid/palladium, reaction time, temperature, and CO pressure have been investigated.

The reaction of benzonitrile oxide with several vinylsilanes has been found to afford silylated isoxazoles.Relative rates for the cycloaddition reaction were determined.