@article { ISI:000364330600008, title = {Highly regioselective isomerizing hydroformylation of long-chain internal olefins catalyzed by a rhodium bis(phosphite) complex}, journal = {ChemCatChem}, volume = {7}, number = {21}, year = {2015}, month = {NOV}, pages = {3468-3471}, publisher = {WILEY-V C H VERLAG GMBH}, address = {POSTFACH 101161, 69451 WEINHEIM, GERMANY}, abstract = {

The single-step synthesis, coordination behavior, and application of a bis(phosphite) ligand in the isomerizing hydroformylation of internal olefins was investigated. Interestingly, high-pressure NMR spectroscopy investigations revealed unexpected inequivalency of the two phosphorus nuclei, which display bisequatorial coordination of the bis(phosphite) ligand in a trigonal bipyramidal rhodium complex. Upon employment in the isomerizing hydroformylation of the exceedingly challenging plant oil derived substrate methyl oleate, the bis(phosphite) rhodium complex revealed an unprecedented linear selectivity of 75\%.

}, keywords = {alkenes, bis(phosphite)s, Hydroformylation, isomerization, Rhodium}, issn = {1867-3880}, doi = {10.1002/cctc.201500743}, author = {Pandey, Swechchha 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 {47805, title = {Hydroformylation of olefins by metals other than rhodium}, journal = {Journal of Organometallic Chemistry}, volume = {960}, year = {2022}, month = {FEB}, pages = {122231}, type = {Article}, abstract = {Metal catalyzed hydroformylation of alkenes is an atom economic transformation to construct useful aldehydes and is being industrially practiced for decades. The most commonly used metal for this transformation on an industrial scale is rhodium. However, rhodium is rare, costly, and is depleting at a skyrocketing rate. Therefore, finding a suitable alternative to rhodium for metal-catalyzed hydroformylation has been on the radar of many academic and industrial researchers. This review presents the scientific advancements reported in the hydroformylation reaction using metals other than rhodium. An overview of recent progress in palladium, iridium, ruthenium, cobalt, platinum, and iron-catalyzed hydroformylation is presented. Hydroformylation of alkenes and alkynes, using syngas as well as syngas surrogates is examined. The evaluation of the current status of non-rhodium metals in hydroformylation suggests that the field is still in a nascent stage and, except cobalt, no other metal poses a significant challenge to the dominance of rhodium. Deep mechanistic understanding of rate-limiting elementary steps in the non-rhodium metals is largely missing and thus only limited success is reported. Intense research on ligand design, mechanistic understanding, and choice of non-rhodium metal precursors may change this scenario in near future.}, keywords = {aldehydes, alkenes, catalysis, Hydroformylation, Non-rhodium metals}, issn = {0022-328X}, doi = {10.1016/j.jorganchem.2021.122231}, author = {Kumar, Rohit and Chikkali, Samir H.} } @article {48283, title = {Computational insights into the iron-catalyze d magnesium-me diate d hydroformylation of alkynes}, journal = {Journal of Organometallic Chemistry}, volume = {986}, year = {2023}, month = {FEB}, pages = {122621}, type = {Article}, abstract = {

Iron is one of the most abundant transition metals in the earth{\textquoteright}s crust. It has attracted a lot of attention due to its low toxicity, bio-compatibility, and high natural abundance. Iron-catalyzed hydroamination, hydroalkoxylation, hydrocarboxylation, hydrosilylation, hydroboration, hydrophosphination, hydromagnesiation, and carbonylation reactions have therefore been developed over the past decades. However, despite many experimental and theoretical studies, a complete mechanistic understanding of iron-catalyzed hydrofunctionalisation at the molecular level has not yet been achieved. In this work, through density functional theory (DFT) calculations, we have shown the most feasible path for the hydroformylation of alkynes for an experimentally studied system. We have looked at the iron salt as a precatalyst without any external donor ligand, and the calculations revealed that hydrometalation followed by beta-hydride elimination was favorable over the direct migration of the beta-hydrogen to carbon. Furthermore, our calculations show that the solvent plays an important role in the hydromagnesiation reaction. Furthermore, we have employed an explicit solvent model, where the attachment of one molecule of solvent to the iron center was seen to stabilize the transition states significantly.(c) 2023 Elsevier B.V. All rights reserved.

}, keywords = {Computational study, Ethylene Assisted Catalysis, EtMgBr Assistance, Explicit Role of Solvent, Hydroformylation, Iron Catalyst}, issn = {0022-328X}, doi = {10.1016/j.jorganchem.2023.122621}, author = {Sharma, Himanshu and Tewari, Tanuja and Chikkali, Samir H. and Vanka, Kumar} } @article {48311, title = {Iron-catalyzed magnesium-mediated formal hydroformylation of alkynes and alkenes}, journal = {ChemCatChem}, volume = {15}, year = {2023}, month = {FEB }, type = {Article}, abstract = {

Alkynes and alkenes are routinely converted to corresponding synthetically versatile aldehydes using rhodium-catalyzed hydroformylation. However, rhodium is rare, precious, costly, and depleting at a considerably high rate. Reported here is iron-catalyzed, magnesium-mediated, formal hydroformylation of alkynes and alkenes in the absence of syngas. Readily available FeCl2 in the presence of alkyl magnesium halide, and dimethyl formamide, catalyzes hydroformylation of various alkynes and selectively produces alpha,beta-unsaturated aldehydes in good to excellent conversion. Mechanistic investigations revealed the presence of vinyl magnesium intermediate, the kinetic study disclosed the first-order dependence of the reaction on iron loading, and the control experiment authenticated the iron catalyst{\textquoteright}s homogeneous nature. The scope of this methodology was amplified, and 20 alkenes were examined. [Fe(acac)(3)] in the presence of ligand, alkyl magnesium halide, and dimethyl formamide catalyzed the hydroformylation of alkenes and displayed good to excellent conversion. An earth-abundant iron catalyst offering a syngas cylinder-free safe alternative to high-pressure hydroformylation has been reported.

}, keywords = {aldehydes, alkenes, Alkynes, Hydroformylation, iron catalysis}, issn = {1867-3880}, doi = {10.1002/cctc.202201394}, author = {Tewari, Tanuja and Kumar, Rohit and Chikkali, Samir H.} }