Abstract
Background: Phosphine-free Pd-catalytic platforms, i) combination with chitosan-
Schiff base (CS-Py/Pd), ii) immobilized on chitosan-Schiff base (CS-Py@Pd), and iii) anchored
to modified carbon nanotube support (CNT@CS-Py@Pd),
Methods: They were evaluated regarding a novel pathway for the cross-coupling reaction of
arylboronic acids with acid chlorides.
Results: The CS-Py@Pd platform had the highest catalytic efficiency of the three platforms,
yielding moderate to excellent yields of diaryl ketones.
Conclusion: The catalytic activity of the Pd-catalyst was highly dependent upon the manufacturing
process and type of support.
Keywords:
Phosphine-free Pd-catalyst, Chitosan-Schiff base@Pd, CNT@chitosan-Schiff base@Pd, arylboronic acids, diaryl ketones, coupling reaction.
Graphical Abstract
[5]
Olah, G.A. Freidel-Crafts Chemistry, (Interscience monographs on organic chemistry); Wiley & Sons: New York, 1973.
[10]
Li, J.J.; Gribble, G.N. Palladium in Heterocyclic Chemistry: A Guide for the Synthetic Chemist, 2nd ed; Elsevier, 2016.
[18]
LaBerge, N.A.; Love, J.A. Nickel-catalyzed decarbonylative coupling of aryl esters and arylboronic acids. Eur. J. Org. Chem., 2015, 5538-5546.
[49]
Bykov, V.V.; Korolev, D.N.; Bumagin, N.A. Palladium-catalyzed reactions of organoboron compounds with acyl chlorides. Russ. Chem. Bull. Int. Ed, 1997, 46, 1631-1638.
[56]
Xin, B.; Zhang, Y.; Cheng, K. The surfactant-promoted cross-coupling reactions of Arylboronic Acids with Carboxylic Anhydrides or Acyl Chlorides in water. Synthesis, 2007, 1970-1978.
[65]
Muniyappan, N.; Sabiah, S. Synthesis, structure, and characterization of picolyl- and benzyl-linked biphenyl palladium N-heterocyclic carbene complexes and their catalytic activity in acylative cross-coupling reactions. Appl. Organometal. Chem., 2020, 2020, e5421.
[66]
There are several examples using chitosan@Pd catalytic systems for the performance of traditional coupling of boronic acid with halo(pseudo) compounds; see, Baran, T.; Baran, N.Y.; Menteş A. Sustainable chitosan/starch composite material for stabilization of palladium nanoparticles: Synthesis, characterization and investigation of catalytic behaviour of Pd@chitosan/starch nanocomposite in Suzuki–Miyaura reaction. Appl. Organomet. Chem., 2018, 32, e4075.