0000000000237547
AUTHOR
Samer Saleh
A straightforward copper-free palladium methodology for the selective alkynylation of a wide variety of S-, O-, and N-based mono- and diheterocyclic bromides and chlorides
Abstract High-yield alkynylations are successfully achieved by a simple and widely accessible catalytic system for an unprecedented variety of heterocyclic bromides and chlorides in position -2, -3 or -5: pyridine, quinoline, thiophene, furan, thiazole, benzothiazole, pyrimidine, pyridazine, pyrazine, dioxepin halides are efficiently functionalized in short time reactions. This copper-free methodology employs 1 mol % palladium only, with inexpensive PPh3 and amine base. The ionic liquid solvent allows a straigtforward separation of products and recycling opportunity. Unsuitable substrates and secondary reactions are also reported in order to point out further progress in cross-coupling usin…
Linear Triphosphines as Ligands for Metal Complexes Immobilization in Ionic Liquids: Palladium-Catalyzed Methoxylation of Alkynes
Several novel palladium triphosphine complexes have been synthesized and tested as recyclable catalysts for the methoxylation of alkynes into acetals in ionic liquids. A complete conversion of phenylacetylene was achieved with only 0.2% of (Pd(Triphos)NCMe)((PF6)2) in a methanol/(BMIM)(BF4) mixture. We discovered that the addition of an ionic liquid to methanol allowed not only to increase the activity of the palladium catalyst but also to provide a recyclable catalyst which can be reused several times with a weaker drop of activity. To complete these catalytic studies, we describe the synthesis of the first poor -electron-donating/strong -electron-acceptor linear Triphosphine which, afte…
ChemInform Abstract: A Straightforward Copper-Free Palladium Methodology for the Selective Alkynylation of a Wide Variety of S-, O-, and N-Based Mono- and Diheterocyclic Bromides and Chlorides.
Abstract High-yield alkynylations are successfully achieved by a simple and widely accessible catalytic system for an unprecedented variety of heterocyclic bromides and chlorides in position -2, -3 or -5: pyridine, quinoline, thiophene, furan, thiazole, benzothiazole, pyrimidine, pyridazine, pyrazine, dioxepin halides are efficiently functionalized in short time reactions. This copper-free methodology employs 1 mol % palladium only, with inexpensive PPh3 and amine base. The ionic liquid solvent allows a straigtforward separation of products and recycling opportunity. Unsuitable substrates and secondary reactions are also reported in order to point out further progress in cross-coupling usin…
ChemInform Abstract: Donor-Stabilized Phosphenium Adducts as New Efficient and Immobilizing Ligands in Palladium-Catalyzed Alkynylation and Platinum-Catalyzed Hydrogenation in Ionic Liquids.
The straightforward synthesis of a new donor-stabilized phosphenium ligand 3d by addition of bromodifurylphosphine to 1,3-dimethylimidazolium-2-carboxylate 1 is described. The obtained ligand exhibits a very strong π-acceptor character, comparable to that of triphenyl phosphite [P(OPh) 3 ] or of tris-halogenophosphines, with a v CO (A 1 ) at 2087 cm ―1 for its nickel tricarbonyl complex. This ligand, as well as the related 3a which was obtained from chlorodiphenylphosphine, were tested in palladium-catalyzed aryl alkynylation and in the platinum-catalyzed selective hydrogenation of chloronitrobenzenes, both in an ionic liquid phase. In C―C bond cross-coupling we observed that the increase o…
Donor-Stabilized Phosphenium Adducts as New Efficient and Immobilizing Ligands in Palladium-Catalyzed Alkynylation and Platinum-Catalyzed Hydrogenation in Ionic Liquids
The straightforward synthesis of a new donor-stabilized phosphenium ligand 3d by addition of bromodifurylphosphine to 1,3-dimethylimidazolium-2-carboxylate 1 is described. The obtained ligand exhibits a very strong π-acceptor character, comparable to that of triphenyl phosphite [P(OPh) 3 ] or of tris-halogenophosphines, with a v CO (A 1 ) at 2087 cm ―1 for its nickel tricarbonyl complex. This ligand, as well as the related 3a which was obtained from chlorodiphenylphosphine, were tested in palladium-catalyzed aryl alkynylation and in the platinum-catalyzed selective hydrogenation of chloronitrobenzenes, both in an ionic liquid phase. In C―C bond cross-coupling we observed that the increase o…
Uncommon perspectives in palladium- and copper-catalysed arylation and heteroarylation of terminal alkynes following Heck or Sonogashira protocols: Interactions copper/ligand, formation of diynes, reaction and processes in ionic liquids
Abstract Conjugated alkynes are recurring building blocks in natural products and in a wide range of important compounds, such as pharmaceuticals, agrochemicals, or molecular materials. The palladium-catalysed cross-coupling reaction between the sp 2 -hybridized carbon atoms of aryl, heteroaryl, and vinyl halides with the sp -hybridized carbon atoms of terminal alkynes is one of the most important developments in the field of alkyne chemistry over the past 50 years. Room for improvement still exists in these important reactions of direct arylation of terminal alkynes. In this prospect, the present authors have developed several strategies aiming at improving the reactivity, the selectivity,…