The Experts below are selected from a list of 1041 Experts worldwide ranked by ideXlab platform
Jonathan R. Scheerer - One of the best experts on this subject based on the ideXlab platform.
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Synthesis of (±)-acetylnorloline via stereoselective tethered Aminohydroxylation.
Organic letters, 2011Co-Authors: M. Todd Hovey, Emily J. Eklund, Robert D. Pike, Anshul A. Mainkar, Jonathan R. ScheererAbstract:Loline alkaloids exhibit a strained ether-bridged pyrrolizidine skeleton and possess insecticidal and insect antifeedant properties. The synthesis of acetylnorloline, a prototypical member of the alkaloid family, is described. Central to the route is a stereoselective tethered Aminohydroxylation (TA) of a homoallylic carbamate. Allylic (A1,3) strain is exploited to enforce diastereofacial selectivity during the Aminohydroxylation.
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synthesis of acetylnorloline via stereoselective tethered Aminohydroxylation
Organic Letters, 2011Co-Authors: Todd M Hovey, Emily J. Eklund, Robert D. Pike, Anshul A. Mainkar, Jonathan R. ScheererAbstract:Loline alkaloids exhibit a strained ether-bridged pyrrolizidine skeleton and possess insecticidal and insect antifeedant properties. The synthesis of acetylnorloline, a prototypical member of the alkaloid family, is described. Central to the route is a stereoselective tethered Aminohydroxylation (TA) of a homoallylic carbamate. Allylic (A1,3) strain is exploited to enforce diastereofacial selectivity during the Aminohydroxylation.
Pradeep Kumar - One of the best experts on this subject based on the ideXlab platform.
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A general and concise asymmetric synthesis of sphingosine, safingol and phytosphingosines via tethered Aminohydroxylation.
Organic & biomolecular chemistry, 2010Co-Authors: Pradeep Kumar, Abhishek Dubey, Vedavati G. PuranikAbstract:A novel, practical and efficient enantioselective synthesis of sphingoid bases, L-threo-[2S,3S]-sphinganine (safingol), L-threo-[2S,3S]-sphingosine, L-arabino-[2R,3S,4R] and L-xylo-[2R,3S,4S]-C18-phytosphingosine is described. The synthetic strategy features the Sharpless kinetic resolution and tethered Aminohydroxylation (TA) as the key steps.
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Synthesis of (−)-galantinic acid via iterative hydrolytic kinetic resolution and tethered Aminohydroxylation
Tetrahedron, 2010Co-Authors: Abhishek Dubey, Shruti Vandana Kauloorkar, Pradeep KumarAbstract:Abstract A new synthetic strategy for (−)-galantinic acid is reported using iterative hydrolytic kinetic resolution and tethered Aminohydroxylation as the key steps.
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An asymmetric Aminohydroxylation route to cis-2,6-disubstituted piperidine-3-ol : application to the synthesis of (-)-deoxocassine
Tetrahedron, 2006Co-Authors: Subba Rao V Kandula, Pradeep KumarAbstract:Abstract A highly efficient, flexible, and convergent route to cis-2,3,6-trisubstituted piperidines has been developed employing the Sharpless asymmetric Aminohydroxylation and stereoselective reductive amination by catalytic hydrogenation as the key steps. Its usage is illustrated by the short synthesis of the piperidine-3-ol alkaloid, (−)-deoxocassine.
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An asymmetric Aminohydroxylation route to (+)-l-733,060
Tetrahedron: Asymmetry, 2005Co-Authors: Subba Rao V Kandula, Pradeep KumarAbstract:Abstract An enantioselective synthesis of (+)- l -733,060 starting from cinnamic acid using Sharpless asymmetric Aminohydroxylation and Wittig reactions as the key steps is described.
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application of the asymmetric Aminohydroxylation reaction for the syntheses of hiv protease inhibitor hydroxyethylene dipeptide isostere and γ amino acid derivative
Tetrahedron Letters, 2004Co-Authors: Nagendra B Kondekar, Subba Rao V Kandula, Pradeep KumarAbstract:An enantioselective synthesis of lactone 1, a precursor to the (2R,4S,5S) hydroxyethylene dipeptide isostere and amino acid AHPPA 2 has been accomplished from the common intermediate 5 employing Sharpless asymmetric Aminohydroxylation as the key step.
A. Richard Chamberlin - One of the best experts on this subject based on the ideXlab platform.
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Synthesis of the dysiherbaine tetrahydropyran core utilizing improved tethered Aminohydroxylation conditions.
Tetrahedron letters, 2011Co-Authors: Christopher L. Carroll, A. Richard ChamberlinAbstract:Abstract A concise stereoselective route to the dysiherbaine tetrahydropyran core was achieved in nine steps and 39% overall yield. Donohoe’s improved tethered Aminohydroxylation conditions were employed to concurrently install the amino and alcohol groups and construct the tetrahydropyran ring, which features four contiguous cis -stereocenters.
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Synthesis of the dysiherbaine tetrahydropyran core employing a tethered Aminohydroxylation reaction.
Tetrahedron letters, 2007Co-Authors: Jamie L. Cohen, A. Richard ChamberlinAbstract:A stereocontrolled and scalable synthesis of an advanced intermediate of the dysiherbaine tetrahydropyran core has been achieved in 11 steps and 27% overall yield. The key feature of this synthetic approach is the application of the Donohoe tethered Aminohydroxylation reaction to install the amino diol and establish the four contiguous syn stereocenters on the tetrahydropyran ring.
K. Barry Sharpless - One of the best experts on this subject based on the ideXlab platform.
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The Osmium‐Catalyzed Aminohydroxylation of Baylis—Hillman Olefins.
ChemInform, 2010Co-Authors: Wallace Pringle, K. Barry SharplessAbstract:Abstract The Baylis-Hillman class of olefins undergoes a facile osmium-catalyzed Aminohydroxylation reaction. The diastereoselectivity for the Aminohydroxylation is influenced by the aldehyde-derived substituent, while the acrylate-derived substituent has a minimal effect. A variety of derivatives and close analogs of the Baylis-Hillman product-core failed to aminohydroxylate, emphasizing the unique reactivity of this class of olefins.
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Primary amides. A general nitrogen source for catalytic asymmetric Aminohydroxylation of olefins.
Organic letters, 2000Co-Authors: Zachary Demko, And Michael Bartsch, K. Barry SharplessAbstract:N-Bromo,N-lithio salts of primary carboxamides have been shown to be efficient nitrogen sources for catalytic asymmetric Aminohydroxylation of olefins, behaving much like the parent N-bromoacetamide in these reactions. α-Chloro-N-bromoacetamide is a particularly interesting nitrogen source, as it is functionalized for further reaction, including easy deprotection by treatment with thiourea.
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Tert-butylsulfonamide. A new nitrogen source for catalytic Aminohydroxylation and aziridination of olefins.
Organic letters, 1999Co-Authors: Alexander V. Gontcharov, And Hong Liu, K. Barry SharplessAbstract:The N-chloramine salt of tert-butylsulfonamide has been shown to be an efficient nitrogen source and the terminal oxidant for catalytic Aminohydroxylation and aziridination of olefins, resembling closely Chloramine-T by its behavior in these catalytic reactions. The sulfonyl−nitrogen bond in the product or its derivatives is easily cleaved under mild acidic conditions, allowing for facile liberation of the amino group.
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THE OSMIUM-CATALYZED Aminohydroxylation OF BAYLIS-HILLMAN OLEFINS
Tetrahedron Letters, 1999Co-Authors: Wallace Pringle, K. Barry SharplessAbstract:Abstract The Baylis-Hillman class of olefins undergoes a facile osmium-catalyzed Aminohydroxylation reaction. The diastereoselectivity for the Aminohydroxylation is influenced by the aldehyde-derived substituent, while the acrylate-derived substituent has a minimal effect. A variety of derivatives and close analogs of the Baylis-Hillman product-core failed to aminohydroxylate, emphasizing the unique reactivity of this class of olefins.
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Reversal of regioselection in the asymmetric Aminohydroxylation of cinnamates
Tetrahedron Letters, 1998Co-Authors: Gunther Schlingloff, K. Barry SharplessAbstract:Abstract Use of cinchona ligands with an anthraquinone (AQN) core, in place of the usual phthalazine (PHAL) core, in the asymmetric Aminohydroxylation of cinnamates causes dramatic reversal of the regioselection, so that phenyl serines are obtained in high enantiomeric excess. Hence, the regioselectivity outcome (i.e. isoserine vs. serine) is controlled by the ligand and not the substrate.
Nakjeong Kim - One of the best experts on this subject based on the ideXlab platform.
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a new synthetic route to cassine via asymmetric Aminohydroxylation
Tetrahedron Letters, 2007Co-Authors: Guncheol Kim, Nakjeong KimAbstract:Abstract (−)-Cassine has been synthesized by a new route, asymmetric Aminohydroxylation followed by reductive amination.
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A new synthetic route to (−)-cassine via asymmetric Aminohydroxylation
Tetrahedron Letters, 2007Co-Authors: Guncheol Kim, Nakjeong KimAbstract:Abstract (−)-Cassine has been synthesized by a new route, asymmetric Aminohydroxylation followed by reductive amination.