Pd2+-catalyzed oxidative aminocarbonylation of O-2,3-butadienyl and O-3,4-pentadienyl N-tosylcarbamates

Palladium-catalyzed oxidative carbonylation reactions

Palladium-catalyzed coupling reactions have become a powerful tool for advanced organic synthesis. This type of reaction is of significant value for the preparation of pharmaceuticals, agrochemicals, as well as advanced materials. Both, academic as well as industrial laboratories continuously investigate new applications of the different methodologies. Clearly, this area constitutes one of the major topics in homogeneous catalysis and organic synthesis. Among the different palladium-catalyzed coupling reactions, several carbonylations have been developed and widely used in organic syntheses and are even applied in the pharmaceutical industry on ton-scale. Furthermore, methodologies such as the carbonylative Suzuki and Sonogashira reactions allow for the preparation of interesting building blocks, which can be easily refined further on. Although carbonylative coupling reactions of aryl halides have been well established, palladium-catalyzed oxidative carbonylation reactions are also interesting. Compared with the reactions of aryl halides, oxidative carbonylation reactions offer an interesting pathway. The oxidative addition step could be potentially avoided in oxidative reactions, but only few reviews exist in this area. In this Minireview, we summarize the recent development in the oxidative carbonylation reactions.

Palladium(II)-catalyzed three-component coupling reaction initiated by acetoxypalladation of alkynes: an efficient route to gamma,delta-unsaturated carbonyls

[formula: see text] A divalent palladium-catalyzed coupling reaction of electron-deficient alkynes and acrolein or MVK (methyl vinyl ketone) was developed. The reaction provides an efficient method to synthesize gamma,delta-unsaturated carbonyls. A mechanism involving acetoxypalladation of alkyne, followed by insertion of alkene and protonolysis of the C-Pd bond, is proposed. The protonolysis of the carbon-palladium bond with the assistance of bidentate nitrogen containing ligands is the key step in this tandem reaction.

Palladium(II)-catalyzed tandem reaction of intramolecular aminopalladation of allenyl N-tosylcarbamates and conjugate addition

A divalent palladium-catalyzed tandem cyclization-coupling reaction of allenyl N-tosylcarbamates and acrolein was developed. The reaction gave aldehyde-functionalized 2-oxazolidinones in one step with high regioselectivity. A mechanism involving intramolecular aminopalladation of allene, followed by insertion of alkene and C-Pd bond protonolysis, is proposed. [reaction: see text]