01595nas a2200181 4500008004100000022001400041245008700055210006900142260011000211300001400321490000700335520085400342100002301196700002301219700002801242700002701270856011601297 2016 eng d a1463-926200aLigand-free Pd catalyzed cross-coupling reactions in an aqueous hydrotropic medium0 aLigandfree Pd catalyzed crosscoupling reactions in an aqueous hy aTHOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLANDbROYAL SOC CHEMISTRYcNOV a1898-19110 v183 a

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.

1 aJadhav, Sanjay, N.1 aKumbhar, Arjun, S.1 aRode, Chadrashekhar, V.1 aSalunkhe, Rajashri, S. uhttps://library.ncl.res.in/content/ligand-free-pd-catalyzed-cross-coupling-reactions-aqueous-hydrotropic-medium01617nas a2200193 4500008004100000022001400041245014700055210006900202260000800271300001200279490000700291520087500298100002101173700002301194700002901217700002601246700002301272856012801295 2020 eng d a0340-428500aBio-surfactant: a green and environmentally benign reaction medium for ligand-free Pd-catalyzed Mizoroki-Heck cross-coupling reaction in water0 aBiosurfactant a green and environmentally benign reaction medium cSEP a403-4110 v453 a

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] .

1 aPatil, Seema, P.1 aJadhav, Sanjay, N.1 aRode, Chandrashekhar, V.1 aShejwal, Rajendra, V.1 aKumbhar, Arjun, S. uhttps://library.ncl.res.in/content/bio-surfactant-green-and-environmentally-benign-reaction-medium-ligand-free-pd-catalyzed02194nas a2200265 4500008004100000022001400041245011500055210006900170260000800239300001400247490000800261520130100269653001001570653001801580653002501598653002101623653000901644100002101653700002501674700002301699700002401722700002901746700002301775856013001798 2024 eng d a1011-372X00aZrO2 supported Cu nanoparticles for sonogashira and ullmann coupling reactions under palladium-free conditions0 aZrO2 supported Cu nanoparticles for sonogashira and ullmann coup cJUN a3078-30900 v1543 a

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 ``traditional'' 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

10aCuNPs10aRecyclability10aSonogashira coupling10aUllmann coupling10aZrO21 aPatil, Seema, P.1 aRajmane, Archana, S.1 aJadhav, Sanjay, N.1 aRajmane, Vijaya, S.1 aRode, Chandrashekhar, V.1 aKumbhar, Arjun, S. uhttps://library.ncl.res.in/content/zro2-supported-cu-nanoparticles-sonogashira-and-ullmann-coupling-reactions-under-palladium