02570nas a2200193 4500008004100000245012300041210006900164260000800233300001600241490000700257520185100264100001702115700002502132700002402157700002002181700002502201700002002226856013002246 2011 eng d00aNew CNN-type ruthenium pincer NHC complexes. synthesis and catalytic activity. mild, efficient hydrogenation of esters0 aNew CNNtype ruthenium pincer NHC complexes synthesis and catalyt cJUN a3826–38330 v303 a

New pincer ruthenium complexes (2–6) based on the new bipyridine-NHC ligand 1 were prepared and studied, resulting in an efficient catalytic hydrogenation of esters to the corresponding alcohols under mild conditions. Reaction of the ligand 1 with RuH(Cl)CO(PPh3)3, followed by reaction with one equivalent of the base KHMDS, gave the mixed phosphine-NHC complex 2, incorporating a C–H-activated bipyridine ligand. Complex 2 has an octahedral structure containing two phosphorus atoms trans to each other, a hydride trans to the NHC ligand, and CO trans to the C–H-activated carbon of the bipyridine ligand. Using the precursor complex Ru(p-cymene)Cl2(CO), reaction with 1 followed by treatment of the intermediate product with one equivalent of KHMDS resulted in formation of the dichloride pincer complexes 3a and 3b, which are in equilibrium, as indicated by variable-temperature 1H NMR. Complex 3a is an octahedral, neutral, and symmetric complex with the CO ligand positioned trans to the central pyridine group of the pincer ligand and the two chlorides trans to each other, as indicated by single-crystal X-ray diffraction. Complex 3b is cationic, with an outer-sphere chloride. Reaction of the NHC ligand 1 with LiHMDS at low temperature followed by addition of RuH(Cl)CO(PPh3)3 resulted in the mixed phosphine-NHC complex 4, which has an octahedral structure containing phosphorus trans to the hydride, a CO trans to the NHC ligand, and an outer-sphere chloride. Chloride substitution by BArF– gave the X-ray-characterized complex 5. Deprotonation of complex 4 with KHMDS resulted in formation of the dearomatized complex 6. The in situ prepared 6 (from complex 4 and an equivalent of base) is among the best catalysts known for the hydrogenation of nonactivated esters to the corresponding alcohols under mild conditions.

1 aFogler, Eran1 aBalaraman, Ekambaram1 aBen-David, Yehoshoa1 aLeitus, Gregory1 aShimon, Linda, J. W.1 aMilstein, David uhttp://library.ncl.res.in/content/new-cnn-type-ruthenium-pincer-nhc-complexes-synthesis-and-catalytic-activity-mild-efficient01873nas a2200157 4500008004100000245013500041210006900176260000800245520121900253100002001472700002501492700002801517700002801545700001601573856012601589 2012 eng d00aNovel ruthenium complexes and their uses in processes for formation and/or hydrogenation of esters, amides and derivatives thereof0 aNovel ruthenium complexes and their uses in processes for format cOCT3 a

The present invention relates to novel Ruthenium complexes and related borohydride complexes, and their use for (1) hydrogenation of amides (including polyamides) to alcohols and amines; (2) preparing amides from alcohols with amines (including preparing polyamides (e.g., polypeptides) by reacting dialcohols and diamines or by polymerization of amino alcohols); (3) hydrogenation of esters to alcohols (including hydrogenation of cyclic esters (lactones), cyclic di-esters (di-lactones) or polyesters); (4) hydrogenation of organic carbonates (including polycarbonates) to alcohols and of carbamates (including polycarbamates) or urea derivatives to alcohols and amines; (5) dehydrogenative coupling of alcohols to esters; (6) hydrogenation of secondary alcohols to ketones; (7) amidation of esters (synthesis of amides from esters and amines); (8) acylation of alcohols using esters; (9) coupling of alcohols with water to form carboxylic acids; and (10) dehydrogenation of beta-amino alcohols to form pyrazines. The present invention further relates to novel uses of certain pyridine Ruthenium complexes.

1 aMilstein, David1 aBalaraman, Ekambaram1 aGunanathan, Chidambaram1 aGnanaprakasam, Boopathy1 aZhang, Jing uhttp://library.ncl.res.in/content/novel-ruthenium-complexes-and-their-uses-processes-formation-andor-hydrogenation-esters01258nas a2200193 4500008004100000245015300041210006900194260000800263300001400271490000600285520048300291100003000774700002500804700002000829700002400849700002400873700002500897856014200922 2016 eng d00aNickel-catalyzed direct alkynylation of C(sp2)-H bonds of amides: an “inverse sonogashira strategy” to ortho-alkynylbenzoic acids. just accepted0 aNickelcatalyzed direct alkynylation of Csp2H bonds of amides an  cOCT a1946-19510 v63 a

Nickel-catalyzed direct alkynylation of C(sp2)–H bonds of amides using commercially available, inexpensive 8-aminoquinoline as a removable bidentate directing group is described. The present ortho-alkynylation has a broad substrate scope, functional group tolerance and high regiocontrol, and can be scaled up. The efficiency and selectivity of this strategy provide sustainable routes to a diverse array of ortho-alkynylbenzoic acids under Ni(II)-catalyzed conditions.

1 aLandge, Vinod, Gokulkrish1 aShewale, Chinmay, H.1 aJaiswal, Garima1 aSahoo, Manoj, Kumar1 aMidya, Siba, Prasad1 aBalaraman, Ekambaram uhttp://library.ncl.res.in/content/nickel-catalyzed-direct-alkynylation-csp2-h-bonds-amides-%E2%80%9Cinverse-sonogashira-strategy%E2%80%9D01110nas a2200169 4500008004100000245006400041210006300105260000800168300001400176490000800190520054700198100002600745700001800771700003100789700002500820856009500845 2017 eng d00aNickel-catalyzed direct synthesis of dialkoxymethane ethers0 aNickelcatalyzed direct synthesis of dialkoxymethane ethers cAUG a1153-11590 v1293 aA simple and efficient method for the preparation of dialkoxymethane ethers (oxymethylene ethers) from alcohols and paraformaldehyde in the presence of commercially available nickel(II) salt is described. The reaction proceeds readily under neutral, solvent-free conditions using paraformaldehyde as a C-1 source. The present strategy has a broad substrate scope including aliphatic (both primary and secondary) and aromatic alcohols and provides a benign method for the preparation of symmetrical dialkoxymethanes in good yields (up to 89%).1 aSubaramanian, Murugan1 aBera, Abhijit1 aPrasad, Bhagavatula, L. V.1 aBalaraman, Ekambaram uhttp://library.ncl.res.in/content/nickel-catalyzed-direct-synthesis-dialkoxymethane-ethers01377nas a2200301 4500008004100000022001400041245008300055210006900138260000800207300001500215490000700230520045900237653001500696653002400711653001300735653002000748653001200768653001800780653001200798653001600810653001600826653003000842100002200872700002000894700002600914700002500940856011000965 2017 eng d a1477-052000aNickel-catalyzed N-vinylation of heteroaromatic amines via C-H bond activation0 aNickelcatalyzed Nvinylation of heteroaromatic amines via CH bond cSEP a 6896-69000 v153 a

Here, we report a ligand- and reductant-free nickel-catalyzed N-vinylation of heteroaromatic amines using biorenewable p-cymene as a solvent. This unprecedented cross-coupling strategy has high functional group tolerance (halides, alkoxy, cyano, chiral motif, etc.) and proceeded via C-H bond activation.

10aAlkylation10aAmination Reactions10aAnilines10aAryl Chlorides10ahalides10aMonoarylation10aO Bonds10aPrecatalyst10aPyrimidines10aRemoveble Directing Group1 aLandge, Vinod, G.1 aRana, Jagannath1 aSubaramanian, Murugan1 aBalaraman, Ekambaram uhttp://library.ncl.res.in/content/nickel-catalyzed-n-vinylation-heteroaromatic-amines-c-h-bond-activation01485nas a2200193 4500008004100000245011800041210006900159260000800228300001400236490000700250520076300257100002001020700002001040700002701060700003001087700001901117700002501136856013001161 2018 eng d00a Ni-catalyzed alpha-alkylation of unactivated amides and esters with alcohols by hydrogen auto-transfer strategy 0 aNicatalyzed alphaalkylation of unactivated amides and esters wit cNOV a3911-39160 v113 aA transition-metal-catalyzed borrowing hydrogen/hydrogen auto-transfer strategy allows the utilization of feedstock alcohols as an alkylating partner, which avoids the formation of stoichiometric salt waste and enables a direct and benign approach for the construction of C-N and C-C bonds. In this study, a nickel-catalyzed alpha-alkylation of unactivated amides and ester (tert-butyl acetate) is carried out by using primary alcohols under mild conditions. This C-C bond-forming reaction is catalyzed by a new, molecularly defined nickel(II) NNN-pincer complex (0.1-1 mol %) and proceeds through hydrogen auto-transfer, thereby releasing water as the sole byproduct. In addition, N-alkylation of cyclic amides under Ni-catalytic conditions is demonstrated.1 aMidya, Siba, P.1 aRana, Jagannath1 aPitchaimani, Jayaraman1 aNandakumar, Avanashiappan1 aMadhu, Vedichi1 aBalaraman, Ekambaram uhttp://library.ncl.res.in/content/ni-catalyzed-alpha-alkylation-unactivated-amides-and-esters-alcohols-hydrogen-auto-transfer01183nas a2200169 4500008004100000245010600041210006900147260000800216300001400224490000600238520056500244100002000809700001700829700002600846700002500872856011600897 2018 eng d00aNi-catalyzed dehydrogenative coupling of primary and secondary alcohols with methyl-N-heteroaromatics0 aNicatalyzed dehydrogenative coupling of primary and secondary al cNOV a3250-32550 v53 aHere we report the first base-metal catalyzed dehydrogenative coupling of primary (aromatic, heteroaromatic, and aliphatic) and secondary alcohols with methyl-N-heteroaromatics to form various C(sp(3))-alkylated N-heteroaromatics. The reaction is enabled by Earth abundant, non-precious NiBr2 as a transition metal catalyst and N,N,N,N-tetramethylethylenediamine (TMEDA) as a ligand system. Mechanistic studies reveal that a hydrogen auto-transfer process is involved in the direct C(sp(3))-alkylation and the reaction proceeds through an -olefination process.1 aRana, Jagannath1 aBabu, Reshma1 aSubaramanian, Murugan1 aBalaraman, Ekambaram uhttp://library.ncl.res.in/content/ni-catalyzed-dehydrogenative-coupling-primary-and-secondary-alcohols-methyl-n00864nas a2200193 4500008004100000022001400041245010400055210006900159260000900228300001400237490000700251520018500258100002200443700001800465700002600483700002000509700002500529856011600554 2019 eng d a1359-734500aNickel(ii)-catalyzed direct olefination of benzyl alcohols with sulfones with the liberation of H-20 aNickeliicatalyzed direct olefination of benzyl alcohols with sul cMAY  a6130-61330 v553 a

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.

1 aLandge, Vinod, G.1 aYadav, Vinita1 aSubaramanian, Murugan1 aDangarh, Pragya1 aBalaraman, Ekambaram uhttp://library.ncl.res.in/content/nickelii-catalyzed-direct-olefination-benzyl-alcohols-sulfones-liberation-h-201504nas a2200181 4500008004100000022001400041245009600055210006900151260000800220300001400228490000700242520086100249100001801110700002301128700002501151700002401176856012201200 2022 eng d a1523-706000aNickel-catalyzed direct synthesis of N-substituted indoles from amino alcohols and alcohols0 aNickelcatalyzed direct synthesis of Nsubstituted indoles from am cDEC a9054-90590 v243 a

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.

1 aYadav, Vinita1 aJagtap, Sayali, G.1 aBalaraman, Ekambaram1 aMhaske, Santosh, B. uhttp://library.ncl.res.in/content/nickel-catalyzed-direct-synthesis-n-substituted-indoles-amino-alcohols-and-alcohols01988nas a2200205 4500008004100000022001400041245017100055210006900226260000800295300001400303490000700317520119400324100002601518700002801544700002401572700001501596700001701611700002501628856012901653 2024 eng d a2044-475300aNickel-catalyzed tandem conversion of paraformaldehyde : methanol to hydrogen and formate/chemo- and stereoselective hydrogenation of alkynes under neutral conditions0 aNickelcatalyzed tandem conversion of paraformaldehyde methanol t cMAY a2779-27930 v143 a

The development of new catalytic protocols for clean and COx-free hydrogen generation from fundamental feedstocks is always interesting and challenging. Herein, we disclose nickel-catalyzed dihydrogen generation from a mixture of paraformaldehyde-methanol under base-free and activator-free conditions. The dihydrogen generation from this redox combination under neutral, oxidative coupling conditions has been integrated with the hydrogen transfer reactions such as chemo- and stereoselective hydrogenation of alkynes in a tandem manner. This unprecedented strategy provides diverse highly stereoselective olefins with excellent tolerance of reducible functional groups such as ether, silyl ether, aldehyde, keto, ester, nitrile, halides including bromo and iodo groups, and heteroarenes. Additionally, we demonstrated catalytic stereo-interconversion of alkenes under benign conditions. The affordable gram-scale synthesis of some important pharmaceutical bioactive molecules has further enhanced their synthetic value. A tandem dihydrogen generation from a mixture of paraformaldehyde-methanol under base-free conditions followed by semihydrogenation of alkynes is reported.

1 aSubaramanian, Murugan1 aPadhy, Subarna, Sukanya1 aGouda, Chandrakanth1 aDas, Tamal1 aVanka, Kumar1 aBalaraman, Ekambaram uhttp://library.ncl.res.in/content/nickel-catalyzed-tandem-conversion-paraformaldehyde-methanol-hydrogen-and-formatechemo-and