- Pseudo enantiomeric carbohydrate olefin ligands - Case study and application in kinetic resolution in rhodium(I)-catalysed 1,4-addition
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In order to investigate significant differences in asymmetric induction for pseudo enantiomeric carbohydrate olefin ligands in rhodium(I)-catalysed 1,4-addition reactions, we designed a set of new olefin ligands differing in relative configuration and pyranoside conformation. With these, we have successfully elucidated structural requirements for metal binding and also identified an improved alternative for one pseudo enantiomer. Furthermore, we report the efficient kinetic resolution of a racemic 4-hydroxycyclopentenone derivative by 1,4-addition.
- Grugel, Holger,Albrecht, Fabian,Boysena, Mike M. K.
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p. 3289 - 3294
(2015/02/05)
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- Resolution of racemic 4-hydroxy-2-cyclopentenone with immobilized penicillin G acylase
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Enantiomerically pure 4-oxo-2-cyclopentenyl derivatives were prepared by kinetic resolution with penicillin G acylase (EC 3.5.1.11) immobilized on an epoxy activated polymer. The enzyme selectively hydrolyzes the phenylacetyl ester of the (S)-enantiomer t
- Kumaraguru, Thenkrishnan,Fadnavis, Nitin W.
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p. 775 - 779
(2012/09/05)
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- Toward the total syntheses of pepluanin A and euphosalicin: Concise route to a highly oxygenated cyclopentane as a common intermediate
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A substrate controlled asymmetric synthesis is described of a highly functionalized cyclopentanyl vinyl triflate which serves as an advanced intermediate in the total synthesis of the novel multidrug resistance reversing jatrophanes pepluanin A and euphosalicin. Key steps are a Claisen-Eschenmoser rearrangement followed by hydroxy-lactonization, intramolecular trans-lactonization, Davis hydroxylation and regioselective enoltriflate formation.
- Gilbert, Michael W.,Galkina, Anna,Mulzer, Johann
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p. 2558 - 2562
(2007/10/03)
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- 4-Hydroxycyclopent-2-en-1-one and derivatives as chiral synthetic equivalents of cyclopentadienone in asymmetric Diels-Alder reactions
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Endo-tricyclodecadienone 8a and related annelated-cyclopentenones (8b, 20, 21a-c and 22) are synthesized in good chemical yield by a Diels-Alder reaction of 4-hydroxycyclo-pent-2-en-1-one 12a and derivatives 12b-h with an appropriate diene. These additions are considerably accelerated by Lewis catalysts, high pressure and by using water as solvent. Due to opposing steric and electronic effects the diastereofacial selectivity of the asymmetric cycloadditions is moderate. By carefully choosing the substrate and reaction conditions an acceptable π-facial selectivity can be achieved.
- Dols,Klunder,Zwanenburg
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p. 8515 - 8538
(2007/10/02)
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- Kinetic Resolution of Racemic Allylic Alcohols by BINAP-Ruthenium(II)-Catalyzed Hydrogenation
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Chiral allylic secondary alcohols have been resolved efficiently by homogeneous hydrogenation catalyzed by (R)- or (S)-BINAP-Ru diacetate complex.The combined effects of intramolecular and intermolecular asymmetric induction give up to 76:1 differentiation between the enantiomeric unsaturated alcohols.
- Kitamura, Masato,Kasahara, Isamu,Manabe, Kenji,Noyori, Ryoji,Takaya, Hidemasa
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p. 708 - 710
(2007/10/02)
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