01736nas a2200181 4500008004100000022001400041245013100055210006900186260011000255300001600365490000600381520094500387100002501332700002101357700002001378700002501398856013101423 2014 eng d a2046-206900aRole of cation-anion cooperation in the selective synthesis of glycidol from glycerol using DABCO-DMC ionic liquid as catalyst0 aRole of cationanion cooperation in the selective synthesis of gl aTHOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLANDbROYAL SOC CHEMISTRYcJUL a32127-321330 v43 a

Transesterification of dimethyl carbonate with glycerol has been investigated using 1,4-diazabicyclo [2.2.2] octane (DABCO) based ionic liquid as a catalyst. DABCO reacted with dimethyl carbonate to form ionic liquid as the reaction progressed. Though the basicity of DABCO based ionic liquid was lower than that of DABCO, the catalytic activity and selectivity to glycidol was higher with DABCO based ionic liquid as a catalyst, indicating that basicity may not be the only criterion in deciding activity and selectivity of the reaction. The cooperative effect of the cation and anion of the ionic liquid is responsible for the observed results. The best results (97% glycerol conversion with 83% selectivity to glycidol and 17% selectivity to glycerol carbonate) were obtained using DABCO based ionic liquid as a catalyst. A plausible mechanism involving the role of both the cation and anion of the ionic liquid has been proposed.

1 aMunshi, Mudassir, K.1 aGade, Swapna, M.1 aRane, Vilas, H.1 aKelkar, Ashutosh, A. uhttps://library.ncl.res.in/content/role-cation-anion-cooperation-selective-synthesis-glycidol-glycerol-using-dabco-dmc-ionic-002588nas a2200217 4500008004100000022001400041245013100055210006900186260011000255300001600365490000600381520166900387100002902056700002502085700002502110700003102135700002602166700002902192700002502221856012402246 2015 eng d a2046-206900aRhodium complex with unsymmetrical vicinal diamine ligand: excellent catalyst for asymmetric transfer hydrogenation of ketones0 aRhodium complex with unsymmetrical vicinal diamine ligand excell aTHOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLANDbROYAL SOC CHEMISTRYcJUN a51722-517290 v53 a

New unsymmetrical vicinal diamine ligands with systematic variation in the regio and stereo positions in the amine and sulphonamide groups were synthesized from cheap starting material such as norephedrine. Catalytic Asymmetric Transfer Hydrogenation (ATH) of aromatic alkyl ketones has been investigated using transition metal complexes and new derivatives of monotosylated unsymmetrical vicinal diamine ligands using sodium formate as the hydrogen source, in water and methanol. Chiral secondary alcohols were obtained with excellent enantioselectivity (>95% ee) and conversion of ketones (>95%) with [Rh(Cp*)Cl-2](2) and ligand 4 as a catalyst. Enantioselectivity was found to be slightly higher with the use of methanol as a solvent for ATH of ketones with sodium formate as the hydrogen source compared to water as a solvent and was found to be consistent with all the ketones investigated. The reaction mixture is homogeneous in methanol unlike in water, where substrate and product are insoluble in water and form separate phase, sodium formate being soluble in water. The activity and enantioselectivity obtained for ATH of ketones using [Rh(Cp*)Cl-2](2) and unsymmetrical vicinal diamine ligand as catalyst was comparable with the C2 symmetric benchmark ligands like TsDPEN ((1R, 2R)-N-(p-tolylsulfonyl)-1,2-diphenylethylene- diamine), and TsCYDN ((1R, 2R)-N-(p-tolylsulfonyl)-1,2-cyclohexyl, diamine) under similar reaction conditions. To the best of our knowledge, this is first example of the ATH of ketones with good activity and high enantioselectivity with [Rh(Cp*)Cl-2](2) and unsymmetrical vicinal diamine ligands as catalyst systems.

1 aDeshpande, Sudhindra, H.1 aShende, Vaishali, S.1 aShingote, Savita, K.1 aChakravarty, Debamitra, K.1 aPuranik, Vedavati, G.1 aChaudhari, Raghunath, V.1 aKelkar, Ashutosh, A. uhttps://library.ncl.res.in/content/rhodium-complex-unsymmetrical-vicinal-diamine-ligand-excellent-catalyst-asymmetric-001662nas a2200193 4500008004100000022001400041245015400055210006900209260000900278300001600287490000600303520090700309100002501216700001901241700002301260700002501283700002901308856013101337 2019 eng d a2470-134300aRoom-temperature asymmetric transfer hydrogenation of biomass-derived levulinic acid to optically pure gamma-valerolactone using a ruthenium catalyst0 aRoomtemperature asymmetric transfer hydrogenation of biomassderi cNOV  a19491-194980 v43 a

This study presents a first report on ruthenium-catalyzed asymmetric transfer hydrogenation (ATH) of levulinic acid (LA) to chiral gamma-valerolactone (GVL). ATH of LA has been explored with Noyori's chiral catalyst (Ru-TsDPEN) in methanol solvent. Efficacy of ATH reaction of LA was investigated under different reactions conditions such as temperature, catalyst, and hydrogen donor concentration. The effect of various organic tertiary bases along with formic acid (FA) as a hydrogen donor was studied, and N-methylpiperidine with FA (1:1 molar ratio) was revealed as an efficient hydrogen donor for ATH of LA to GVL furnishing chiral GVL with complete conversion and 93% enantiomeric excess (ee). This operationally simple and mild ATH protocol was tested for practical applicability of ATH of LA obtained from biomass waste (rice husk and wheat straw) and furnished chiral GVL with 82% ee.

1 aShende, Vaishali, S.1 aRaut, Amol, B.1 aRaghav, Prathamesh1 aKelkar, Ashutosh, A.1 aBhanage, Bhalchandra, M. uhttps://library.ncl.res.in/content/room-temperature-asymmetric-transfer-hydrogenation-biomass-derived-levulinic-acid-optically