@article { ISI:000256178900015, title = {Selective cis-dihydroxylation of olefins using recyclable homogeneous molybdenum acetylide catalyst}, journal = {Journal of Molecular Catalysis A-Chemical}, volume = {285}, number = {1-2}, year = {2008}, month = {APR}, pages = {111-119}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

Selective cis-dihydroxylation of various olefins has been carried out using molybdenum acetylide complex CpMO(CO)(3)(C CPh) (1) as catalyst and hydrogen peroxide as an efficient and environmentally benign oxidant. In case of cyclohexene, very high conversion (95\%) and selectivity (86\%) for cis-dihydroxylated product has been achieved using H2O2 as an oxidant and t-butanol as a solvent. cis-Dihydroxylation of other substrates like styrene, a-methyl styrene, limonene and cyclopentene has also been carried out with very high selectivity for diol. The catalyst and intermediate species have been characterized using FT-IR, UV-vis spectral analysis and XPS studies as well as cyclic voltametric studies. These studies suggest that molybdenum oxo-peroxo complex is the catalytically active species. The intermediate blue complex when characterized by ESI MS suggested the formation of dimeric molybdenum complex and XPS and cyclic voltametric studies confirm the presence of mixed valence Mo(V) and Mo(VI) in the reaction intermediate. Based on the characterization results possible mechanism for dihydroxylation is proposed. Interestingly, even though the catalyst is homogeneous; it could be recovered quantitatively by extraction in aqueous phase and recycled five times without any appreciable loss in cyclohexene conversion and selectivity for cis-1,2-cyclohexanediol. (c) 2008 Elsevier B.V. All rights reserved.

}, keywords = {acetylide complex, cis-dihydroxylation, Homogeneous catalysis, Hydrogen peroxide, recyclable}, issn = {1381-1169}, doi = {10.1016/j.molcata.2008.01.034}, author = {Biradar, Ankush V. and Sathe, Bhaskar R. and Shubhangi B. Umbarkar and Dongare, Mohan K.} } @article { ISI:000310744400011, title = {Selective oxidation of nonrefractory and refractory sulfides by cyclopentadienyl molybdenum acetylide complexes as efficient catalysts}, journal = {Catalysis Letters}, volume = {142}, number = {11}, year = {2012}, month = {NOV}, pages = {1352-1360}, publisher = {SPRINGER}, address = {233 SPRING ST, NEW YORK, NY 10013 USA}, abstract = {

{The synthesis and catalytic properties of molybdenum acetylide complexes CpMo(CO)(3)(-C CR)

}, keywords = {Homogeneous catalysis, Molybdenum acetylide, Oxo-peroxo species, Refractory sulfide oxidation}, issn = {1011-372X}, doi = {10.1007/s10562-012-0898-x}, author = {Chandgude, Macchindra G. and Biradar, Ankush V. and Kotbagi, Trupti V. and Puranik, Vedavati G. and Dongare, Mohan K. and Shubhangi B. Umbarkar} } @article { ISI:000339493400008, title = {General approach to N-heterocyclic carbenes with a fused tetracyclic core: ligands for suzuki-miyaura cross-coupling reaction}, journal = {European Journal of Organic Chemistry}, number = {21}, year = {2014}, month = {JUL}, pages = {4482-4486}, publisher = {WILEY-V C H VERLAG GMBH}, address = {BOSCHSTRASSE 12, D-69469 WEINHEIM, GERMANY}, abstract = {

The synthesis of an N-heterocyclic carbene (NHC) based on a tetracyclic scaffold by using simple, general, and scalable chemistry is disclosed. The developed route is suitable for introducing multiple substitutions on the tetracyclic scaffold. The utility of the present NHC as a ligand in the Suzuki-Miyaura cross-coupling reaction is demonstrated with a low catalyst loading.

}, keywords = {C-C coupling, carbenes, Homogeneous catalysis, N ligands, synthetic methods}, issn = {1434-193X}, doi = {10.1002/ejoc.201402378}, author = {Sutar, Revannath L. and Kumar, Vinod and Shingare, Rahul D. and Thorat, Shridhar and Gonnade, Rajesh G. and Reddy, D. Srinivasa} } @article { ISI:000348510400004, title = {Catalyst-dependent selectivity in the relay catalytic branching cascade}, journal = {Chemistry-A European Journal}, volume = {21}, number = {6}, year = {2015}, month = {FEB}, pages = {2319-2323}, publisher = {WILEY-V C H VERLAG GMBH}, address = {BOSCHSTRASSE 12, D-69469 WEINHEIM, GERMANY}, abstract = {

The synthesis of small organic molecules as probes for discovering new therapeutic agents has been an important aspect of chemical biology. One of the best ways to access collections of small molecules is to use various techniques in diversity-oriented synthesis (DOS). Recently, a new form of DOS, namely relay catalytic branching cascades (RCBCs), has been introduced, wherein a common type of starting material reacts with several scaffold-building agents (SBAs) to obtain structurally diverse molecular scaffolds under the influence of catalysts. Herein, the RCBC reaction of a common type of substrate with SBAs is reported to give two different types of molecular scaffolds and their formation is essentially dependent on the type of catalyst used.

}, keywords = {alkynols, cascade synthesis, chemoselectivity, diversity-oriented synthesis, Homogeneous catalysis}, issn = {0947-6539}, doi = {10.1002/chem.201405736}, author = {Bansode, Avinash H. and Shaikh, Aslam C. and Kavthe, Rahul D. and Thorat, Shridhar and Gonnade, Rajesh G. and Patil, Nitin T.} } @article { ISI:000362749100016, title = {Modular synthesis of biaryl-substituted phosphine ligands: application in microwave-assisted palladium-catalyzed C-N cross-coupling reactions}, journal = {European Journal of Organic Chemistry}, number = {29}, year = {2015}, month = {OCT}, pages = {6515-6525}, publisher = {WILEY-V C H VERLAG GMBH}, address = {POSTFACH 101161, 69451 WEINHEIM, GERMANY}, abstract = {

Biaryl-substituted monophosphine-based ligands have been synthesized by transition-metal-free ARYNE cross-coupling reaction of aryllithiums with 1,2-dibromobenzene and subsequent regioselective functionalization through bromine-lithium interconversion. These ligands were employed in palladium-catalyzed C-N bond-forming reactions. The reaction was found to be general with wide substrate applicability. A wide variety of both primary and secondary amines were successfully coupled with an array of differently substituted halobenzenes under microwave irradiation to give the expected products in good to excellent yields. A number of biaryl-substituted phosphine ligands screened for the coupling reaction showed that steric bulk and the electronic properties of substituents on phosphorus play a crucial role in governing the catalytic activity of C-N cross-coupling reactions.

}, keywords = {Biaryls, Cross-coupling, Homogeneous catalysis, Microwave chemistry, Palladium, Phosphines, synthetic methods}, issn = {1434-193X}, doi = {10.1002/ejoc.201500962}, author = {Singh, Chandani and Rathod, Jayant and Jha, Vishwajeet and Panossian, Armen and Kumar, Pradeep and Leroux, Frederic R.} } @article {45764, title = {Efficient oxidation of ethyl benzene using in situ generated molybdenum acetylide oxo-peroxo complex as recyclable catalyst}, journal = {Applied Catalysis A-General}, volume = {531}, year = {2017}, month = {FEB }, pages = {45-51}, type = {Article}, abstract = {

Selective oxidation of various alkanes/alkyl aromatics to corresponding carbonyl compounds has been carried out with very high conversion (similar to 98\%) and selectivity (up to 100\%) for carbonyl compounds using cyclopentadienyl molybdenum acetylide complex, CpMo(CO)(3)(C CPh) (1) as catalyst and tert-butyl hydrogen peroxide (TBHP) as an oxidant and turnover number (TON) of 88 was obtained with turnover frequency (TOF) of 2.45 h(-1). Mo acetylide oxo-peroxo species is formed in situ by reaction of 1 with TBHP during the course of reaction as catalytically active species. Interestingly even though the catalytically active species is homogeneous in nature it could be recycled very easily by recovering the catalytically active species as solid after addition of diethyl ether, and separating the products into organic phase. In the case of ethyl benzene oxidation, even after three recycles no appreciable loss in ethyl benzene conversion and acetophenone selectivity was observed. This complex showed high catalytic activity for the oxo functionalization of other alkyl aromatics and alkanes such as substituted ethyl benzenes, toluene as well as cyclohexane. TBHP was found to be more efficient oxidant than hydrogen peroxide for this oxidation. (C) 2016 Elsevier B.V. All rights reserved.

}, keywords = {Alkyl aromatics, Carbonyl compounds, Homogeneous catalysis, Molybdenum acetylide complex, Oxo-peroxo species}, issn = {0926-860X}, doi = {10.1016/j.apcata.2016.12.003}, author = {Khomane, Sonali B. and Doke, Dhananjay S. and Dongare, M. K. and Halligudi, S. B. and Umbarkar, S. B.} } @article {46673, title = {Expeditious and solvent-free nickel-catalyzed c-h arylation of arenes and indoles (vol 10, pg 2242, 2017)}, journal = {ChemSusChem}, volume = {13}, year = {2020}, month = {NOV }, pages = {5771}, type = {Correction}, keywords = {Arylation, C-H activation, heterocycles, Homogeneous catalysis, Nickel}, issn = {1864-5631}, doi = {10.1002/cssc.202002313, Early Access Date = OCT 2020}, author = {Jagtap, Rahul A. and Soni, Vineeta and Punji, Benudhar} } @article {46838, title = {Palladium-catalyzed insertion of ethylene and 1,1-disubstituted difunctional olefins: an experimental and computational study}, journal = {ChemPlusChem}, volume = {85}, year = {2020}, month = {JUN}, pages = {1200-1209}, type = {Article}, abstract = {

Insertion or coordination copolymerization of ethylene with di-substituted olefins is challenging and the choice of di-substituted mono-functional olefin versus di-substituted di-functional olefin (DDO) appears to be decisive. Here we show that DDO-inserted species are amenable to ethylene insertion and polymerization. DDOs such as 2-acetamidoacrylic acid (AAA), methyl 2-acetamidoacrylate (MAAA), and ethyl 2-cyanoacrylate (ECA) were treated with palladium complex [{P perpendicular to O}PdMe(L)] (P perpendicular to O=kappa(2)-P,O-Ar2PC6H4SO2O with Ar=2-MeOC6H4; L=C2H6OS) and the existence of respective insertion intermediates in moderate yield (up to 37 \%) was established. These intermediates were exposed to ethylene and corresponding ethylene-inserted products were isolated and characterized. A careful comparison with three model compounds confirmed ethylene insertion and polymerization. Thus, the combined experimental and computational investigations show that DDO-inserted species can undergo ethylene insertion and polymerization.

}, keywords = {Homogeneous catalysis, insertion copolymerization, Olefins, Palladium, Polyethylene}, issn = {2192-6506}, doi = {10.1002/cplu.202000309}, author = {Gaikwad, Shahaji R. and Patel, Ketan and Deshmukh, Satej S. and Mote, Nilesh R. and Birajdar, Rajkumar S. and Pandole, Satish P. and Chugh, Jeetender and Chikkali, Samir H.} } @article {47038, title = {Phosphorus ligands in hydroformylation and hydrogenation: a personal account}, journal = {Chemical Record}, year = {2021}, month = {MAR}, type = {Article; Early Access}, abstract = {

Metal-catalyzed hydroformylation and hydrogenation heavily rely on ligands, among which phosphorous ligands play a pivotal role. This personal account presents a selection of three distinct classes of phosphorous ligands, namely, monodentate meta-substituted phosphinites, bis-phosphites, and P-chiral supramolecular phosphines, developed in our group. The synthesis of these ligands, isolation, characterization, and their performance in transition metal-catalyzed hydroformylation, isomerizing hydroformylation, and asymmetric hydrogenation of olefins is summarized. The state of the art development in iron-catalyzed hydroformylation of alkenes and our contributions to the field is discussed. Use of phosphines enabled iron-catalyzed hydroformylation of alkenes under mild conditions. Thus, this account demonstrates the central role of phosphorus ligands in industrially relevant transformations such as hydrogenation and hydroformylation. The seemingly matured field of ligand discovery still holds significant potential and will steer the field of homogeneous catalysis.

}, keywords = {Homogeneous catalysis, Hydroformylation, Hydrogenation, Olefins, Phosphorus ligands}, issn = {1527-8999}, doi = {10.1002/tcr.202100007, Early Access Date = MAR 2021}, author = {Tewari, Tanuja and Kumar, Rohit and Chandanshive, Amol C. and Chikkali, Samir H.} } @article {49522, title = {Ruthenium-catalyzed deconstruction of polyolefins: a strategy to up-cycle waste polyethylene to value-added alkene}, journal = {Angewandte Chemie-International Edition}, volume = {64}, year = {2025}, month = {APR}, type = {Article}, abstract = {

Synthesis of value-added products from post-consumer waste polyolefins is fascinating as well as challenging. Here we report ruthenium-catalyzed up-cycling of the polyethylene to long-chain alkene derivatives. The developed methodology mainly involves two steps i.e., dehydrogenation of polyethylene through hydrogen atom transfer and its metathesis using the HG-II catalyst. The dehydrogenation of polyethylene using ruthenium catalysis derived up to 3.38 \%, of double bonds; with 90 \% of the recovered polyolefin material. The obtained unsaturated polyethylene was subjected to cross-metathesis with ethylene using HG-II catalytic system. This resulted in the synthesis of predominantly dodecene (C12) derivatives, with 58 \% selectivity, along with other derivatives of varying chain lengths. The overall reaction produced terminal and internal olefins in the ratio 1:0.8 respectively. The dehydrogenation of polyethylene and its deconstruction was confirmed by NMR spectroscopy, Gel Permeation Chromatography (GPC) and Differential Scanning Calorimetry (DSC). The origin of C12 selectivity has been demonstrated by control experiments. The scope of the methodology was extended to post-consumer waste polyethylene which gave high conversion to value-added dodecene derivatives as a major product.

}, keywords = {Deconstruction, Homogeneous catalysis, ruthenium, Upcycling, Waste plastic}, doi = {10.1002/anie.202422609}, author = {Padhi, Ganeshdev and Khopade, Kishor V. and Moyilla, Nageswararao and Rangappa, Raghavendrakumar and Chikkali, Samir H. and Barsu, Nagaraju} }