@article { ISI:000285387600001,
	title = {Greener ullmann-type coupling of aryl halides for preparing biaryls using reusable Pd/ZrO2 catalyst},
	journal = {Synthetic Communications},
	volume = {41},
	number = {2},
	year = {2011},
	month = {JAN},
	pages = {PII 931249796},
	publisher = {TAYLOR \& FRANCIS INC},
	address = {325 CHESTNUT ST, SUITE 800, PHILADELPHIA, PA 19106 USA},
	abstract = {<p>Biaryls with excellent yields can be prepared by the Ullmann-type coupling of aryl halides in the presence of potassium carbonate (as a base) and dimethylformamide (as a solvent), at 140 degrees C, using a reusable Pd (2.5wt\%)/ZrO2 catalyst. The product yield of 4-iodoanisole coupling is strongly influenced by the catalyst preparation method, solvent, and base.</p>},
	keywords = {Aryl halides, Biaryls, Pd, Ullmann coupling reaction, ZrO2},
	issn = {0039-7911},
	doi = {10.1080/00397910903531805},
	author = {Dumbre, Deepa K. and Wakharkar, Radhika D. and Choudhary, Vasant R.}
}
@article {49647,
	title = {ZrO2 supported Cu nanoparticles for sonogashira and ullmann coupling reactions under palladium-free conditions},
	journal = {Catalysis Letters},
	volume = {154},
	year = {2024},
	month = {JUN},
	pages = {3078-3090},
	type = {Article},
	abstract = {<p>
	Cu nanoparticles supported on ZrO2 (CuNPs@ZrO2) were synthesized using a one-step co-precipitation process, and their application in C-C coupling reactions was investigated. The catalyst was characterized using XRD, XPS, SEM, TEM, and TGA techniques. The prepared catalyst was used for the Sonogashira cross-coupling reactions of aryl bromides with phenyl-acetylene in the presence of K2CO3 in DMF at 110 degrees C, which resulted in substituted alkynes with good to excellent yields. The protocol was also extended for the Ullmann coupling reactions of aryl iodides under similar reaction conditions, yielding the desired products with good to excellent yields without homo-coupling. Interestingly, unlike other copper catalysts, the present catalyst worked under air and did not require an inert atmosphere to prevent alkyne. This catalytic system is versatile, tolerant, and significantly cheaper than the {\textquoteleft}{\textquoteleft}traditional{\textquoteright}{\textquoteright} Pd-catalyzed Sonogashira cross-coupling of terminal alkynes with aryl halides. The catalyst could be reused for five catalytic cycles with no significant change in the product yield. All of these characteristics make our prepared CuNPs@ZrO2 catalyst quite suitable for the gram-scale synthesis of biaryls and alkynes, with a simple workup.{GRAPHIACAL ABSTRACT</p>
},
	keywords = {CuNPs, Recyclability, Sonogashira coupling, Ullmann coupling, ZrO2},
	issn = {1011-372X},
	doi = {10.1007/s10562-023-04513-w},
	author = {Patil, Seema P. and Rajmane, Archana S. and Jadhav, Sanjay N. and Rajmane, Vijaya S. and Rode, Chandrashekhar V. and Kumbhar, Arjun S.}
}
