- Asymmetric synthesis of non-natural amino acid derivatives: (2R/3S) and (2S/3R) 2-(tert-butoxycarbonylamino)-3-cyclohexyl-3-phenyl propanoic acids
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Highly conformationally-constrained novel α-amino acid derivatives ((2R/3S ) and (2S/3R )-2-(tert-butoxycarbonylamino)-3- cyclohexyl-3-phenylpropanoic acids) have been synthesised with high stereoselectivity (> 90% de) and in 36-37% overall yields. In the synthesis, Evans' auxiliary (4(R/S )-4-phenyl-oxzaolidin-2-one) was used to control the stereoselectivity via the key reactions of asymmetric Michael addition, azidation and catalytic hydrogenolysis.
- Yang, Rui,Guo, Ya-Fei,Gao, Zhan-Yong,Zhao, Qian,Zhang, Qian-Yang,Lin, Jun
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- Palladium-catalyzed diastereoselective synthesis of β,β-diarylpropionic acid derivatives and its application to the total synthesis of (R)-tolterodine and the enantiomer of a key intermediate for MK-8718
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Palladium-catalyzed diastereoselective synthesis of optically active β,β-diarylpropionic acid derivatives employing 4-(tert-butyl)oxazolidin-2-one as the chiral auxiliary under an air atmosphere in excellent yields with high diastereoselectivity is reported. The catalytic system is applied to the total synthesis of (R)-tolterodine and the enantiomer of a key intermediate for MK-8718.
- Zhi, Wubin,Li, Jingya,Zou, Dapeng,Wu, Yangjie,Wu, Yusheng
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supporting information
p. 537 - 540
(2018/01/17)
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- Conjugate addition of aryl nucleophiles to α,β-unsaturated cinnamic acid derivatives containing Evans type chiral auxiliaries
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Cinnamides containing oxazolidin-2-one type auxiliaries have been prepared. A novel pathway to chiral 4-aryl-6-methyl-3,4-dihydrocoumrines via the asymmetric conjugate addition of arylmagnesium bromides to these cinnamides is described.
- Leitis, Zigmārs,Lūsis, Viesturs
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p. 843 - 851
(2016/09/02)
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- Synthesis of a macrocycle based on Linked Amino Acid Mimetics (LAAM)
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We report the synthesis of a macrocycle utilizing a novel framework of standard amino acids in combination with subunits that we have named as Linked Amino Acid Mimetics (LAAMs). Macrocycles based on the LAAM concept provide both a peptide targeting regio
- Maxwell, David S.,Sun, Duoli,Peng, Zhenghong,Martin, Diana V.,Bhanu Prasad, Basvoju A.,Bornmann, William G.
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supporting information
p. 5799 - 5801
(2013/10/01)
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- Doubly diastereoselective conjugate addition of enantiopure lithium amides to enantiopure N-enoyl oxazolidin-2-ones: A mechanistic probe
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The doubly diastereoselective conjugate addition of the antipodes of lithium N-benzyl-N-(α-methylbenzyl)amide to a range of enantiopure N-enoyl oxazolidin-2-ones has been used as a mechanistic probe to determine that the reactive conformation is the anti-s-cis form. The β-amino carbonyl products resulting from these conjugate addition reactions are useful templates for further elaboration into an α,β,α-pseudotripeptide.
- Davies, Stephen G.,Fletcher, Ai M.,Hermann, Gesine J.,Poce, Giovanna,Roberts, Paul M.,Smith, Andrew D.,Sweet, Miles J.,Thomson, James E.
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experimental part
p. 1635 - 1648
(2010/10/18)
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- Nitrile Ylides: Diastereoselective cycloadditions using chiral oxzolidinones without Lewis acid
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"Chemical Equation Presented" Lewis acid complexation Is generally required for chiral-auxiliary-controlled stereoselectivity, and chiral Lewis acid catalysis Is frequently optimal for Introducing asymmetry. In this work, we show that nitrlle ylide cycloadditions to electron-poor acceptors attached to chiral auxiliaries proceed In high yield and stereoselectivity in the absence of Lewis acids. In contrast, chiral Lewis acids are Inferior In these cycloadditions.
- Mukund P, Sibi,Soeta, Takahlro,Jasperse, Craig P.
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supporting information; experimental part
p. 5366 - 5369
(2010/02/28)
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- Diastereoselective ru-catalyzed cross-metathesis-dihydroxylation sequence. An efficient approach toward enantiomerically enriched syn-diols
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(Chemical Equation Presented) Sequential catalysis has evolved as a powerful concept within the past years and allows the more efficient use of catalytically active expensive transition metals in organic synthesis. In this paper we present the stereoselective cross-metathesis-dihydroxylation of various olefins with chiral auxiliary substituted acrylamides. The chiral information (i.e., the auxiliary) introduced in the metathesis reactions allows for a stereoselective subsequent RuO4-catalyzed dihydroxylation. The sequence is concluded by an unusual kinetic resolution of the diastereomeric diols obtained in the oxidation reaction. As a consequence a variety of structurally diverse enantiomerically enriched diols are obtained. To the best of our knowledge the results summarized in this paper represent the first highly efficient diastereoselective RuO4-catalyzed oxidation.
- Neisius, N. Matthias,Plietker, Bernd
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p. 3218 - 3227
(2008/09/19)
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- NOVEL SPIROTROPANE COMPOUNDS AND METHODS FOR THE MODULATION OF CHEMOKINE RECEPTOR ACTIVITY
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Compounds according to formula (I): wherein the radical R2 represents a hydrogen atom or one of the following structures: R, and R7_9are as herein defined, and wherein ring A represents a 5 or 6 membered heteroring involvi
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Page/Page column 76
(2008/06/13)
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- Spirohydantoin compounds and methods for the modulation of chemokine receptor activity
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Novel compounds represented by formula (I): wherein R1, R2, R3 and R4 are as defined herein, and pharmaceutically acceptable salts, hydrates and solvates thereof, are useful for the modulation of CCR5 chemokine
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Page/Page column 13
(2010/02/15)
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- SPIRO COMPOUNDS AND METHODS FOR THE MODULATION OF CHEMOKINE RECEPTOR ACTIVITY
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Compounds of formula I insert formula I from claim 1 wherein X, Y, Z, W, R1 and R2 as defined herein, or pharmaceutically acceptable salts, hydrates or solvates thereof, are useful for the modulation of CCR5 chemokine receptor activity.
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Page/Page column 104
(2010/02/11)
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