@article {46099, title = {Nickel(ii)-catalyzed direct olefination of benzyl alcohols with sulfones with the liberation of H-2}, journal = {Chemical Communications}, volume = {55}, year = {2019}, month = {MAY }, pages = {6130-6133}, type = {Article}, abstract = {

A nickel(II)-catalyzed direct olefination of benzyl alcohols with sulfones to access various terminal and internal olefins with the liberation of hydrogen gas is reported.

}, issn = {1359-7345}, doi = {10.1039/c9cc02603g}, author = {Landge, Vinod G. and Yadav, Vinita and Subaramanian, Murugan and Dangarh, Pragya and Balaraman, Ekambaram} } @article {46745, title = {Iron-catalyzed direct julia-type olefination of alcohols}, journal = {Journal of Organic Chemistry}, volume = {85}, year = {2020}, month = {AUG }, pages = {9876-9886}, type = {Article}, abstract = {

Herein, we report an iron-catalyzed, convenient, and expedient strategy for the synthesis of styrene and naphthalene derivatives with the liberation of dihydrogen. The use of a catalyst derived from an earth-abundant metal provides a sustainable strategy to olefins. This method exhibits wide substrate scope (primary and secondary alcohols) functional group tolerance amino, nitro, halo, alkoxy, thiomethoxy, and S- and N-heterocyclic compounds) that can be scaled up. The unprecedented synthesis of 1-methyl naphthalenes proceeds via tandem methenylation/double dehydrogenation. Mechanistic study shows that the cleavage of the C-H bond of alcohol is the rate-determining step.

}, issn = {0022-3263}, doi = {10.1021/acs.joc.0c01173}, author = {Landge, Vinod G. and Babu, Reshma and Yadav, Vinita and Subaramanian, Murugan and Gupta, Virendrakumar and Balaraman, Ekambaram} } @article {46993, title = {Manganese-catalyzed alpha-olefination of nitriles with secondary alcohols}, journal = {ACS Catalysis}, volume = {10}, year = {2020}, month = {JAN}, pages = {947-954}, type = {Article}, abstract = {

An expedient catalytic approach for alpha-olefination of nitriles using secondary alcohols with the liberation of molecular hydrogen and water as the only byproducts is reported. This reaction is catalyzed by a molecularly defined manganese(I) pincer complex and operates in the absence of any hydrogen acceptors. A broad range of substrates including cyclic, acyclic, and benzylic alcohols, as well as various nitrile derivatives, such as arylmethyl and heteroarylmethyl nitriles, are employed in the reaction to provide a diverse range of alpha-vinyl nitriles in good to excellent yields. Mechanistic studies showed that the reaction proceeds via dehydrogenative pathway and the activation of alpha(C-H) bond of the alcohol is the rate-determining step.

}, keywords = {acceptorless dehydrogenation, Alcohol, alpha-olefination, Hydrogen, manganese}, issn = {2155-5435}, doi = {10.1021/acscatal.9b02811}, author = {Yadav, Vinita and Landge, Vinod G. and Subaramanian, Murugan and Balaraman, Ekambaram} } @article {47704, title = {Phosphine-free manganese(II)-catalyst enables acceptorless dehydrogenative coupling of alcohols with indoles}, journal = {Advanced Synthesis \& Catalysis}, volume = {363}, year = {2021}, month = {SEP }, pages = {4430-4439}, type = {Article}, abstract = {Herein, an air-stable, molecularly defined NNN-Mn(II) pincer complex catalyzed acceptorless dehydrogenative coupling of alcohols with indoles is reported. A wide variety of symmetrical and unsymmetrical bis(indolyl)methane derivatives as well as some structurally important products such as Vibrindole A, Turbomycin B alkaloid, Antileukemic, and Anticancer agents were synthesized. Mechanistic studies illustrate the importance of the NH moiety in the complex and the crucial role of metal-ligand cooperation during catalysis.}, keywords = {acceptorless dehydrogenation, Alcohol, Indole, manganese, phosphine-free}, issn = {1615-4150}, doi = {10.1002/adsc.202100621}, author = {Yadav, Vinita and Balaraman, Ekambaram and Mhaske, Santosh B.} } @article {47821, title = {Recent advances in liquid organic hydrogen carriers: an alcohol-based hydrogen economy}, journal = {ACS Catalysis}, volume = {11}, year = {2021}, month = {NOV}, pages = {14712-14726}, type = {Article}, abstract = {Energy storage and the use of abundantly available feedstock without contributing to the carbon footprint are two significant global challenges. In this regard, the development of high-performance, low-cost, sustainable, and environmentally friendly energy storage and production systems is crucial to fulfill the growing energy demands of the current society. The use of hydrogen will diversify energy sources as it significantly reduces greenhouse gas emissions and environmental pollution during energy conversion. Although the hydrogen economy is quite beneficial, hydrogen storage is still very challenging, and the existing methods suffer from a lot of problems and drawbacks. The conventional liquefaction and compression hydrogen storage technologies are associated with several challenges, including low storage density, boil-off losses, relatively high costs, and safety and transportation concerns. In recent years, liquid organic hydrogen carrier (LOHC) systems have attained a lot of importance as a substitute for the traditional storage methods. Hydrogen storage and transport using LOHCs are based on two-step cycles, such as (i) loading/storage of hydrogen by catalytic hydrogenation of H2-lean compounds and (ii) unloading/releasing hydrogen by dehydrogenating the resulting H2-rich liquids. Since alcohols are widely accessible from various industrial processes or even from biomass-derived precursors, the catalytic acceptorless dehydrogenation of alcohols is an attractive approach for future hydrogen storage applications. Hence, the catalytic dehydrogenation-hydrogenation of alcohols can be used for the development of alcohol-based LOHC systems which are economical, safe, and easy to handle. Further, they are similar to crude oils under ambient conditions and thus are suitable for use in the current energy infrastructure. This Review covers several essential aspects of these developing efficient and abundantly available LOHC systems for efficient hydrogen storage and transport applications. Additionally, reversible LOHC systems based on the catalytic dehydrogenation-hydrogenation of alcohols and their corresponding carbonyl compounds have been discussed.}, doi = {10.1021/acscatal.1c03283}, url = {https://doi.org/10.1021/acscatal.1c03283}, author = {Yadav, Vinita and Sivakumar, Ganesan and Gupta, Virendrakumar and Balaraman, Ekambaram} } @article {47382, title = {Substrate, catalyst, and solvent: the triune nature of multitasking reagents in hydroboration and cyanosilylation}, journal = {Organometallics}, volume = {40}, year = {2021}, month = {APR}, pages = {1104-1112}, type = {Article}, abstract = {

A truly green chemical process would avoid the use of an external catalyst, while still achieving high efficiency. This has been realized in the very recent past for hydroboration, cyanosilylation, acetalization, and the aza-Michael addition, among other reactions. The current combined computational and experimental study unlocks the secret to how this highly desirable outcome is accomplished: one of the reactants in the process also acts as the catalyst. Specifically, this is shown (i) for the important hydroboration reaction, with pinacolborane (HBpin) as the hydroborating reagent and benzaldehyde, acetophenone, benzoic acid and p-methoxyphenylacetylene as the hydroborated substrates, and (ii) for cyanosilylation, with trimethylcyanosilane (TMSCN) as the cyanosilylating agent and benzaldehyde as the substrate. The mechanistic understanding thus gained has then been further exploited experimentally to bring hydroboration and cyanosilylation closer to experimental conditions in catalysis. These insights can potentially be expanded to the rapidly growing area of solvent-free and internal catalyst chemistry.

}, issn = {0276-7333}, doi = {10.1021/acs.organomet.1c00070}, author = {Dixit, Ruchi and Bisai, Milan Kumar and Yadav, Sandeep and Yadav, Vinita and Sen, Sakya S. and Vanka, Kumar} } @article {47597, title = {Tandem acceptorless dehydrogenative coupling-decyanation under nickel catalysis}, journal = {Journal of Organic Chemistry}, volume = {86}, year = {2021}, month = {JUN}, pages = {7552-7562}, type = {Article}, abstract = {The development of new catalytic processes based on abundantly available starting materials by cheap metals is always a fascinating task and marks an important transition in the chemical industry. Herein, a nickel-catalyzed acceptorless dehydrogenative coupling of alcohols with nitriles followed by decyanation of nitriles to access diversely substituted olefins is reported. This unprecedented C=C bond-forming methodology takes place in a tandem manner with the formation of formamide as a sole byproduct. The significant advantages of this strategy are the low-cost nickel catalyst, good functional group compatibility (ether, thioether, halo, cyano, ester, amino, N/O/S heterocycles; 43 examples), synthetic convenience, and high reaction selectivity and efficiency.}, issn = {0022-3263}, doi = {10.1021/acs.joc.1c00592}, author = {Midya, Siba P. and Subaramanian, Murugan and Babu, Reshma and Yadav, Vinita and Balaraman, Ekambaram} } @article {48343, title = {Nickel-catalyzed direct synthesis of N-substituted indoles from amino alcohols and alcohols}, journal = {Organic Letters}, volume = {24}, year = {2022}, month = {DEC}, pages = {9054-9059}, type = {Article}, abstract = {

A one-pot cascade approach for the synthesis of N substituted indoles from amino alcohols and alcohols under additive and base-free conditions with the liberation of water as the only stoichiometric byproduct is reported. The commercially available bench-stable Ni(OTf)2 salt in combination with 1,2-bis(dicyclohexylphosphino)ethane (dcype) is very effective for this unprecedented catalytic transformation. A broad range of substrates including aromatic and aliphatic primary alcohols, cyclic and acyclic secondary alcohols, and various substituted 2-aminophenyl ethyl alcohols are employed in the reaction conditions to provide a diverse range of N-alkylated indoles. Mechanistic studies revealed that the reaction proceeds through tandem N-alkylation via hydrogen autotransfer followed by the cyclization of N-alkylated alcohol intermediate.

}, issn = {1523-7060}, doi = {10.1021/acs.orglett.2c03617}, author = {Yadav, Vinita and Jagtap, Sayali G. and Balaraman, Ekambaram and Mhaske, Santosh B.} } @article {49332, title = {Regio- and stereoselective construction of 1,3,5-triaroylcyclohexanes via KO t Bu-mediated cyclotrimerization of aryl vinyl ketones}, journal = {Journal of Organic Chemistry}, volume = {89}, year = {2024}, month = {NOV }, pages = {17207-17212}, type = {Article}, abstract = {

Herein, we disclose a simple one-pot method for an efficient regio- and stereoselective synthesis of 1,3,5-triaroylcyclohexanes from aryl vinyl ketones using potassium tert-butoxide. The developed protocol allows the construction of various symmetrically substituted cyclohexanes in good to excellent yields. The major product 2 also can be converted to the product 3 (all equatorial) conveniently by acid catalysis. This protocol features a good substrate scope and functional group compatibility.

}, issn = {0022-3263}, doi = {10.1021/acs.joc.4c01695}, author = {Mahale, Sachin D. and Yadav, Vinita and Gonnade, Rajesh G. and Mhaske, Santosh B.} }