@article {CSIR, title = {Hydrogenation of polar bonds catalysed by ruthenium-pincer complexes}, journal = {Ruthenium in Catalysis}, volume = {48}, number = {5}, year = {2014}, note = {3rd International Conference on Advances in Computing, Communications and Informatics (ICACCI), New Delhi, INDIA, SEP 24-27, 2014}, month = {MAR}, pages = {19-43}, publisher = {IEEE Commun Soc; IEEE Syst Man \& Cybernet Soc; Galgotias Coll Engn \& Technol; Hochschule Offenburg Univ Appl Sci; Int Neural Network Soc; India Chapter \& Res Publishing Serv; Madhyam; WizIQ; ICACCI; IEEE}, address = {HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY}, abstract = {

Catalytic hydrogenation of polar bonds using molecular hydrogen is an important, atom-economical synthetic reaction. Classical reduction methods of polar bond often require reactive metal-hydride reagents in stoichiometric amount and produce copious waste. Hydrogenation of carbonyl compounds in particular provides {\textquoteleft}green{\textquoteright} approaches to synthetically important building blocks, such as alcohols and amines. We have designed and synthesized several ruthenium-based pincer catalysts for unprecedented hydrogenation reactions including: (1) amides to alcohols and amines, (2) biomass-derived di-esters to 1,2-diols and (3) CO2 and CO derivatives to methanol. These atom-economical reactions operate under neutral, homogeneous conditions, at mild temperatures, mild hydrogen pressures, and can operate in absence of solvent with no generation of waste. The postulated mechanisms involve metal-ligand cooperation (MLC) by aromatization-dearomatization of the heteroaromatic pincer core.

}, keywords = {Amides, Carbon dioxide, Esters, Hydrogen, Hydrogenation, Metal-ligand cooperation, Pincer complexes, ruthenium}, isbn = {978-3-319-08482-4; 978-3-319-08481-7}, issn = {1436-6002}, doi = {10.1007/3418_2014_77}, author = {Balaraman, Ekambaram and Milstein, David}, editor = {Bruneau, C. and Dixneuf, P. H.} } @article {49322, title = {Manganese-catalyzed chemoselective direct hydrogenation of α,β-epoxy ketones and α-ketoamides at room temperature}, journal = {Advanced Synthesis \& Catalysis}, volume = {366}, year = {2024}, month = {AUG}, pages = {3338-3345}, type = {Article}, abstract = {

Chemoselective hydrogenation of alpha,beta-epoxy ketones and alpha-ketoamides is achieved at room temperature (25 degrees C) using 2.0 bar H-2 and a pincer-ligated Mn(I) catalyst that provides synthetically valuable alpha-hydroxy epoxides and alpha-hydroxy amides. This protocol applies to a wide range of alkyl- and aryl-substituted alpha,beta-epoxy ketones, including terpenes (alpha-ionone, nootkatone, and R-carvone)- and steroids (testosterone and progesterone)-derived epoxy ketones, and tolerates H-2 sensitive functionalities, such as halides, acetyl, nitrile, nitro, epoxide, alkenyl and alkynyl groups. Additionally, alpha-ketoamides bearing reducible functional groups, including acetyl and diazo benzene, were untouched under this protocol and selectively converted to alpha-hydroxy amides. A preliminary mechanistic study highlighted the metal-ligand cooperative H-2 activation process.

}, keywords = {alpha, beta-epoxy ketones, chemoselectivity, direct hydrogenation, manganese, Metal-ligand cooperation}, issn = {1615-4150}, doi = {10.1002/adsc.202400267}, author = {Shabade, Anand B. and Singh, Rahul K. and Gonnade, Rajesh G. and Punji, Benudhar} } @article {49023, title = {Nickel-catalyzed chemodivergent coupling of alcohols: efficient routes to access α,α-disubstituted ketones and α-substituted chalcones}, journal = {Chemistry- a european journal}, volume = {30}, year = {2024}, month = {MAR}, type = {Article}, abstract = {

Chemodivergent (de)hydrogenative coupling of primary and secondary alcohols is achieved utilizing an inexpensive nickel catalyst, (6-OH-bpy)NiCl2. This protocol demonstrates the synthesis of branched carbonyl compounds, alpha,alpha-disubstituted ketones, and alpha-substituted chalcones via borrowing hydrogen strategy and acceptorless dehydrogenative coupling, respectively. A wide range of aryl-based secondary alcohols are coupled with various primary alcohols in this tandem dehydrogenation/hydrogenation reaction. The nickel catalyst, along with KOtBu or K2CO3, governed the selectivity for the formation of branched saturated ketones or chalcones. A preliminary mechanistic investigation confirms the reversible dehydrogenation of alcohols to carbonyls via metal-ligand cooperation (MLC) and the involvement of radical intermediates during the reaction. The chemodivergent nickel-catalyzed approach provides alpha,alpha-disubstituted ketones from aryl-substituted secondary alcohols and benzyl alcohols via the borrowing hydrogen (BH) strategy in the presence of KOtBu, whereas exclusively alpha-substituted chalcones were accomplished in the presence of mild base K2CO3 through an acceptorless dehydrogenative coupling (ADC) strategy. image

}, keywords = {Alcohols, dehydrogenative coupling, Metal-ligand cooperation, Nickel, substituted carbonyl compounds}, issn = {0947-6539}, doi = {10.1002/chem.202304082}, author = {Bansal, Sadhna and Punji, Benudhar} }