@article { ISI:000372981400010, title = {Ligand-free Pd catalyzed cross-coupling reactions in an aqueous hydrotropic medium}, journal = {Green Chemistry}, volume = {18}, number = {7}, year = {2016}, month = {NOV}, pages = {1898-1911}, publisher = {ROYAL SOC CHEMISTRY}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

A simple, efficient and ligand-free protocol for the Suzuki-Miyaura reaction and base-free Heck-Matsuda reactions under mild reaction conditions have been developed over palladium supported on activated carbon (Pd/C) in an aqueous hydrotropic solution. The catalyst Pd/C was fully characterized by TG-DTA, SEM, EDS, XRD, XPS, BET and ICP-AES analyses. This green methodology represents a cost-effective and operationally convenient method for the synthesis of a variety of biaryls, prochiral ketones, and acrylates under the conditions that are tolerant for a broad range of functional groups with good to excellent yields. The developed Pd/C-aqueous hydrotrope combined catalytic system is well suited for the 3R approach (reducible, robust, and recyclable) for different cross-coupling reactions without an appreciable loss of its activity.

}, issn = {1463-9262}, doi = {10.1039/c5gc02314a}, author = {Jadhav, Sanjay N. and Kumbhar, Arjun S. and Rode, Chadrashekhar V. and Salunkhe, Rajashri S.} } @article {46825, title = {Bio-surfactant: a green and environmentally benign reaction medium for ligand-free Pd-catalyzed Mizoroki-Heck cross-coupling reaction in water}, journal = {Transition Metal Chemistry}, volume = {45}, year = {2020}, month = {SEP}, pages = {403-411}, type = {Article}, abstract = {

A simple and efficient protocol for the ligand-free Mizoroki-Heck coupling reaction of various aryl bromides with different olefins has been reported by using in situ generated PdNPs of size 5-10 nm in aqueous solution of bio-surfactant. The bio-surfactant used in this study is a saponin extract of the seeds of pericarps (pods) of theAcacia concinnaplant. The in situ generated PdNPs have been characterized by various techniques such as HRTEM, EDS and XPS. The influence of various parameters such as the nature and amount of bases, the nature of Pd precatalysts as well as the effect of temperature has been investigated on Mizoroki-Heck coupling reaction. The generated PdNPs significantly coupled the various aryl bromides with different olefins in aqueous extract of the seeds of pericarps (pods) of theAcacia concinnaplant at 100 degrees C. [GRAPHICS] .

}, issn = {0340-4285}, doi = {10.1007/s11243-020-00392-x, Early Access Date = JUN 2020}, author = {Patil, Seema P. and Jadhav, Sanjay N. and Rode, Chandrashekhar V. and Shejwal, Rajendra V. and Kumbhar, Arjun S.} } @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 = {

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

}, 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.} }