The Experts below are selected from a list of 1047 Experts worldwide ranked by ideXlab platform
Ulrike Nettekoven - One of the best experts on this subject based on the ideXlab platform.
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Preparation of tricyclic imidazopyridines by asymmetric Ketone hydrogenation in the presence of ruthenium phosphino-oxazoline catalyst
Tetrahedron: Asymmetry, 2007Co-Authors: Andreas Palmer, Ulrike NettekovenAbstract:Abstract The asymmetric hydrogenation of the prochiral Heterocyclic Ketone 2 and its O-protected analogues 9 to 11 in the presence of the ruthenium POX catalyst RuCl 2 (PPh 3 )(Ph 2 P-Fc-oxa i Pr) was studied. The reactivity of the substrate and the enantioselectivity of the reduction depended on the nature of the protecting group. The best results were achieved with the thexyldimethylsilyl protecting group: the corresponding alcohol 13 was obtained in 86% yield and 88% ee and constitutes a valuable intermediate for the synthesis of the potassium-competitive acid blocker BYK 311319 1 .
Dhileepkumar Krishnamurthy - One of the best experts on this subject based on the ideXlab platform.
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Catalytic asymmetric hydrogenation of Heterocyclic Ketone-derived hydrazones, pronounced solvent effect on the inversion of configuration
Tetrahedron Letters, 2011Co-Authors: Nizar Haddad, Sonia Rodriguez, Lars Van Der Veen, Diana C. Reeves, Nina C. Gonnella, Heewon Lee, Nelu Grinberg, Dhileepkumar KrishnamurthyAbstract:Abstract An enantioselective hydrogenation of hydrazones derived from Heterocyclic Ketones was developed with up to 85% ee. The enantiomeric purity was enriched to >99% ee by crystallization from EtOAc in >80% yield. Optimization studies have revealed a notable solvent effect that resulted in inversion of enantioselectivity from 85% ee in MeOH to −27% ee in DCE. The hydrazone geometry and possible hydrogenation via endocyclic alkene were examined as possible factors for the inversion of enantioselectivity.
Andreas Palmer - One of the best experts on this subject based on the ideXlab platform.
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Preparation of tricyclic imidazopyridines by asymmetric Ketone hydrogenation in the presence of ruthenium phosphino-oxazoline catalyst
Tetrahedron: Asymmetry, 2007Co-Authors: Andreas Palmer, Ulrike NettekovenAbstract:Abstract The asymmetric hydrogenation of the prochiral Heterocyclic Ketone 2 and its O-protected analogues 9 to 11 in the presence of the ruthenium POX catalyst RuCl 2 (PPh 3 )(Ph 2 P-Fc-oxa i Pr) was studied. The reactivity of the substrate and the enantioselectivity of the reduction depended on the nature of the protecting group. The best results were achieved with the thexyldimethylsilyl protecting group: the corresponding alcohol 13 was obtained in 86% yield and 88% ee and constitutes a valuable intermediate for the synthesis of the potassium-competitive acid blocker BYK 311319 1 .
Truesdell Susan Jane - One of the best experts on this subject based on the ideXlab platform.
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Highly Enantioselective Reduction of a Small Heterocyclic Ketone: Biocatalytic Reduction of Tetrahydrothiophene-3-one to the Corresponding (R)-Alcohol
Organic Process Research & Development, 2010Co-Authors: Jack Liang, Emily Mundorff, Rama Voladri, Stephan Jenne, Lynne Gilson, Aaron Conway, Anke Krebber, John W. Wong, Gjalt W. Huisman, Truesdell Susan JaneAbstract:By leveraging enzyme evolution technologies, the enantioselectivity of a KetoREDuctase (KRED) towards the nearly spatially symmetrical Ketone tetrahydrothiophene-3-one was increased from 63% ee to 99.3% ee. The biocatalytic process gives (R)-tetrahydrothiophene-3-ol in one step from a commodity chemical and supplants the original multistep hazardous processes starting from the chiral pool. The biocatalytic process has been successfully scaled to 100 kg.
Nizar Haddad - One of the best experts on this subject based on the ideXlab platform.
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Catalytic asymmetric hydrogenation of Heterocyclic Ketone-derived hydrazones, pronounced solvent effect on the inversion of configuration
Tetrahedron Letters, 2011Co-Authors: Nizar Haddad, Sonia Rodriguez, Lars Van Der Veen, Diana C. Reeves, Nina C. Gonnella, Heewon Lee, Nelu Grinberg, Dhileepkumar KrishnamurthyAbstract:Abstract An enantioselective hydrogenation of hydrazones derived from Heterocyclic Ketones was developed with up to 85% ee. The enantiomeric purity was enriched to >99% ee by crystallization from EtOAc in >80% yield. Optimization studies have revealed a notable solvent effect that resulted in inversion of enantioselectivity from 85% ee in MeOH to −27% ee in DCE. The hydrazone geometry and possible hydrogenation via endocyclic alkene were examined as possible factors for the inversion of enantioselectivity.