A robust multifunctional ligand-controlled palladium-catalyzed carbonylation reaction in water

Abstract

A novel, hydrophilic and recyclable methoxypolyethylene glycol (PEG)-modulated s-triazine-based multifunctional Schiff base/N,P-ligand L9 was prepared and used in Pd-catalyzed Heck-type carbonylative coupling reactions, affording diverse chalcone derivatives and 1,4-dicarbonyl esters in good yields.

Synthesis of Hydrophilic Phosphorus Ligands and Their Application in Aqueous‐Phase Metal‐Catalyzed Reactions

“…For this purpose, a mPEG 2000 chain was introduced instead of a methoxy group during the ligand synthesis (Scheme 35). [74] …”

“…Poorer yields, however, were obtained in the case of aryl triflates bearing strong electron‐withdrawing groups. Moreover, the Pd‐catalyst in the carbonylative Heck coupling could be reused for five times although suffering from decreasing yields [74] …”

Palladium-catalysed Suzuki–Miyaura coupling of α,β-unsaturated superactive triazine esters

“…19 Our group and others explored aryl acid triazine esters as an acylating reagent in Pd-catalysed C–C cross-coupling reactions. 20 Using triazine as a key element, we synthesized multifunctional phosphine ligands 21 and NHC ligands 22 for Pd-catalysed carbonylative coupling reactions. In light of triazine's unique ability to activate C acyl –O bonds and its catalytic implications, we envisioned superactive triazine esters of α,β-unsaturated carboxylic acids as potent acyl electrophiles for Pd catalysis.…”

“…As shown in Table 2, a broad range of superactive triazine esters is compatible, converting into α,β-enones in generally high to excellent yields. Bearing in mind the privilege of chalcone structure in medicinal chemistry, 21 we explored the coupling of cinnamic triazine esters with 4-methoxyl-phenylboronic acid. The electron-donating, including para ( 24 , 25 ), meta ( 26 ), and sterically hindered ortho ( 27 ) substitution patterns as well as the electron-withdrawing ( 28–31 ) cinnamic triazine esters provided satisfactory yields.…”

Acylative Kinetic Resolution of Cyclic Hydroxamic Acids

“…Others, e.g., 4 , find applications in asymmetric catalysis and assignment of the absolute configurations of amines . While racemic approaches to chiral hydroxamic acids are numerous and often straightforward, their preparation in enantioenriched form is less well-developed. Only a few enantioselective catalytic methods have been described (Figure , eqs 1–3) .…”