- 2,2′-Bipyridine-α,α′-trifluoromethyl-diol ligand: Synthesis and application in the asymmetric Et2Zn alkylation of aldehydes
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A chiral 2,2′-bipyridine ligand (1) bearing α,α′-trifluoromethyl-alcohols at 6,6′-positions was designed in five steps affording either the R,R or S,S enantiomer with excellent stereoselectivities, i.e. 97% de, >99% ee and >99.5% de, >99.5% ee, respectively. The key step for reaching high levels of stereoselectivity was demonstrated to be the resolution of the α-CF3-alcohol using (S)-ibuprofen as the resolving agent. An initial application for the 2,2′-bipyridine-α,α′-CF3-diol ligand was highlighted in the ZnII-catalyzed asymmetric ethylation reaction of aromatic, heteroaromatic, and aliphatic aldehydes. Synergistic electron deficiency and steric hindrance properties of the newly developed ligand afforded the corresponding alcohols in good to excellent yields (up to 99%) and enantioselectivities (up to 95% ee). As observed from single crystal diffraction analysis, the complexation of the 2,2′-bipyridine-α,α′-CF3-diol ligand generates an unusual hexacoordinated ZnII.
- Lauzon, Samuel,Ollevier, Thierry
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supporting information
p. 11025 - 11028
(2021/11/03)
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- Manganese-catalyzed homogeneous hydrogenation of ketones and conjugate reduction of α,β-unsaturated carboxylic acid derivatives: A chemoselective, robust, and phosphine-free in situ-protocol
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We communicate a user-friendly and glove-box-free catalytic protocol for the manganese-catalyzed hydrogenation of ketones and conjugated C[dbnd]C[sbnd]bonds of esters and nitriles. The respective catalyst is readily assembled in situ from the privileged [Mn(CO)5Br] precursor and cheap 2-picolylamine. The catalytic transformations were performed in the presence of t-BuOK whereby the corresponding hydrogenation products were obtained in good to excellent yields. The described system offers a brisk and atom-efficient access to both secondary alcohols and saturated esters avoiding the use of oxygen-sensitive and expensive phosphine-based ligands.
- Topf, Christoph,Vielhaber, Thomas
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- DMF Dimethyl Acetal as Carbon Source for α-Methylation of Ketones: A Hydrogenation-Hydrogenolysis Strategy of Enaminones
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A novel heterogeneous catalytic hydrogenation-hydrogenolysis strategy has been developed for the α-methylation of ketones via enaminones using DMF dimethyl acetal as carbon source. This strategy provides a very convenient route to α-methylated ketones using a variety of ketones without any base or oxidant. (Chemical Equation Presented).
- Borah, Ashwini,Goswami, Limi,Neog, Kashmiri,Gogoi, Pranjal
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p. 4722 - 4728
(2015/05/13)
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- NOVEL PYRIMIDINE COMPOUNDS HAVING BENZYL (HETEROCYCLIC METHYL) AMINE STRUCTURE AND MEDICAMENT COMPRISING THE SAME
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A compound represented by the following general formula (I), wherein R1, R2, R3, R4 and R5 represent hydrogen atom, a halogen atom, a lower alkyl group and the like, R6 represents an alkyl group, a cycloalkyl group and the like, R7 and R8 represent hydrogen atom, a lower alkyl group, a (lower cycloalkyl)(lower alkyl) group and the like, R9 represents hydrogen atom, a halogen atom, a lower alkoxy group and the like, R10 and R11 represent hydrogen atom, a lower alkyl group, a lower alkoxy group, a halo(lower alkyl) group and the like, and A represents a heterocyclic ring constituted by 6 to 10 atoms, which has potent inhibitory activity on cholesterol ester transfer protein (CETP).
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Page/Page column 31
(2009/04/24)
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- NOVEL PYRIMIDINE COMPOUND HAVING DIBENZYLAMINE STRUCTURE AND MEDICAMENT COMPRISING THE SAME
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A compound represented by the following general formula (I), wherein R1, R2, R3, R4 and R5 represent hydrogen atom, a halo(lower alkyl) group, cyano group and the like, R6 represents an alk
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Page/Page column 29
(2009/04/24)
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- Thiourea inhibitors of herpes viruses. Part 2: N-Benzyl-N′- arylthiourea inhibitors of CMV
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A series of highly potent thiourea inhibitors of cytomegalovirus (CMV) with improved stability properties was prepared and evaluated. Compound 29 inhibited the virus in cultured HFF cells with IC50 of 0.2nM.
- Bloom, Jonathan D.,Dushin, Russell G.,Curran, Kevin J.,Donahue, Fran,Norton, Emily B.,Terefenko, Eugene,Jones, Thomas R.,Ross, Adma A.,Feld, Boris,Lang, Stanley A.,DiGrandi, Martin J.
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p. 3401 - 3406
(2007/10/03)
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