Pd(0)–polyethyleneimine complex as a partial hydrogenation catalyst of alkynes to alkenes

Palladium nanoparticle catalysts in ionic liquids: synthesis, characterisation and selective partial hydrogenation of alkynes to Z-alkenes

“…Other examples on this topic for Pdnanocatalysts are rare. [39][40][41][42] These are useful intermediates for the preparation of an enormous number of bioactive molecules and natural products. 14,[43][44][45][46][47][48][49]…”

Additive‐free Semihydrogenation of an Alkynyl Group to an Alkenyl Group over Pd−TiO2 Photocatalyst Utilizing Temporary In‐situ Deactivation

“…From these results, the following advantage of this photocatalytic semihydrogenation over Pd−TiO 2 can be added: 4) Pd−TiO 2 can be used for semihydrogenation of hydrocarbon alkynes. From the four advantages, it is apparent that the present photocatalytic method using Pd−TiO 2 and methanol is superior to the thermocatalytic method using the Lindlar's catalyst in which additives, H 2 gas and continuous monitoring are required …”

Carbon‐11 carboxylation of terminal alkynes with [11C]CO2

“…[7][8][9][10] Among [carbonyl- 11 C]carboxylic acids, 11 C-labelled propiolic acid derivatives have gained interest because this synthon is present in bioactive molecules such as flavones and coumarins and are amenable to further reactions to produce: (a) propargyl alcohols via a selective reduction of the carboxylic group, 11 (b) alkene or alkane carboxylic acids via a selective reduction of the alkyne function, 12,13 and (c) aliphatic alcohols via a reduction of both alkyne and carboxylic groups. 11,13 Given the importance of 11 C-labelled propiolic acid derivatives, several strategies have been applied to carboxylate terminal alkynes with [ 11 C]CO 2 starting from Grignard reagents, 14 boronic esters 15 and trimethylsilyl derivatives. 16,17 Grignard reagents are highly reactive species limiting their application to simple substrates as they are incompatible with many functional groups.…”

“…Carbon dioxide ([ 11 C]CO 2 ) can be directly incorporated into a variety of biologically relevant molecules, forming products such as [carbonyl- 11 C]carboxylic acids, [carbonyl- 11 C]amides, and [carbonyl- 11 C]carbammate. [7][8][9][10] Among [carbonyl- 11 C]carboxylic acids, 11 C-labelled propiolic acid derivatives have gained interest because this synthon is present in bioactive molecules such as flavones and coumarins and are amenable to further reactions to produce: (a) propargyl alcohols via a selective reduction of the carboxylic group, 11 (b) alkene or alkane carboxylic acids via a selective reduction of the alkyne function, 12,13 and (c) aliphatic alcohols via a reduction of both alkyne and carboxylic groups. 11,13 Given the importance of 11 C-labelled propiolic acid derivatives, several strategies have been applied to carboxylate terminal alkynes with [ 11 C]CO 2 starting from Grignard reagents, 14 boronic esters 15 and trimethylsilyl derivatives.…”