- Synthesis of C2 symmetric primary vicinal diamines. Double stereospecific Mitsunobu reaction of the heterocyclic diols derived from tartaric acid
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Homochiral 1-alkyl-3,4-dihydroxypyrrolidines, (S,S)- and (R,R)-5 were obtained by cyclization and reduction of both enantiomers of (+)- and (-)-tartaric acid, respectively. Also (S,S)-3,4-dihydroxytetrahydrofurane 6 was prepared from (+)-diethyl tartrate. All these heterocyclic vic-diols underwent twofold Mitsunobu reaction (Ph3P/DEA/HN3) followed by catalytic hydrogenation forming stereospecifically the corresponding primary vicinal diamines (R,R)-, (S,S)-2 and (R,R)-3. The absolute configuration of diamines 2, 3 was established by the exciton-coupling CD spectra of their N,N'-diphthaloyl derivatives.
- Skarzewski, Jacek,Gupta, Anil
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- PYRROLIDINYL UREA DERIVATIVES AND APPLICATION THEREOF IN TRKA-RELATED DISEASES
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The present invention relates to a class of TrkA inhibitors and an application thereof in the preparation of a drug for the treatment of diseases associated with TrkA. The present invention specifically discloses compounds represented by formula (I) and f
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- Enantioselective trimethylsilylcyanation of benzaldehyde using pyrrolidine-based chiral salen ligands
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The in situ formed Ti(IV) complexes of several pyrrolidine-based chiral salen ligands derived from natural (L)-tartaric acid were evaluated as catalysts in the enantioselective trimethylsilylcyanation of benzaldehyde. The catalysts were found to be very active, producing the corresponding product, O-trimethylsilylmandelonitrile, in high yields (>94%) and enantioselectivities of up to 88%.
- Serra, M. Elisa Silva,Murtinho, Dina,Goth, Albertino
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scheme or table
p. 64 - 69
(2010/08/07)
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- Synthesis of an ovoid chiral cage
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Evidence for the formation of an ovoid chiral cage, resulting from the auto-assembly of two hexafunctional and three tetrafunctional modules reacting through dynamic covalent bond formation, is provided. Georg Thieme Verlag Stuttgart.
- Couty, Fran?ois,David, Olivier R. P.
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scheme or table
p. 1945 - 1948
(2010/04/05)
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- Asymmetric addition of diethylzinc to ketones promoted by tartaric acid derivatives
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The preparation of new sulfonamide ligands derived from L-tartaric acid and camphor sulfonyl chloride are described. The employment in the titanium tetraisopropoxide-promoted enantioselective addition of diethylzinc to ketones has been studied. The best enantiomeric excess is up to 99% with 7 mol% catalyst loading at room temperature. Copyright Taylor & Francis Group, LLC.
- Hui, Ailing,Zhang, Jintang,Wang, Zhiyong
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p. 2374 - 2384
(2008/09/21)
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- anti-Selective direct asymmetric Mannich reactions catalyzed by chiral pyrrolidine-based amino sulfonamides
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The novel pyrrolidine-based amino sulfonamides (R,R)-2, (S)-3, and (S)-4 were designed and synthesized as organocatalysts and successfully applied for the anti-selective direct asymmetric Mannich reaction.
- Kano, Taichi,Hato, Yoshio,Yamamoto, Akihiro,Maruoka, Keiji
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p. 1197 - 1203
(2008/09/18)
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- Design of a C2-symmetric chiral pyrrolidine-based amino sulfonamide: application to anti-selective direct asymmetric Mannich reactions
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The anti-selective direct asymmetric Mannich reaction was found to be efficiently catalyzed by the novel pyrrolidine-based amino sulfonamide (R,R)-2 prepared from l-tartaric acid.
- Kano, Taichi,Hato, Yoshio,Maruoka, Keiji
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p. 8467 - 8469
(2007/10/03)
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- Combinatorial chemistry for ligand development in catalysis: Synthesis and catalysis screening of peptidosulfonamide tweezers on the solid phase
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On the basis of a pyrrolidine tweezer 1, a library of peptidosulfonamide tweezers (15a-e, 16a-e was synthesized on the solid phase. This library was screened in a simultaneous substrate screening procedure for the ability to enantioselectively catalyze the Ti(O-i-Pr)4-mediated addition of diethylzinc to aldehydes. One of the best solid-phase tweezer catalyst (i.e., 16d, giving an ee of 32% in solid-phase catalysis) was resynthesized in solution (compounds 20 and 21). The now homogeneous solution-phase catalysis showed even better enantioselectivity (i.e., up to 66%).
- Brouwer, Arwin J.,van Der Linden, Heiko J.,Liskamp, Rob M. J.
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p. 1750 - 1757
(2007/10/03)
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- Tweezers with different bite: Increasing the affinity of synthetic receptors by varying the hinge part
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With preservation of selectivity, the hinge part of tweezerlike synthetic receptor molecules can be varied to achieve a higher affinity. The synthetic peptidosulfonamide receptor (below left; R = Disperse Red 1) with the bis(aminomethyl)benzoic acid hinge selectively bound the tripeptide shown below on the right (K(a) = 4100 M-1). Combination of a diversity in the hinge part with that present in the tweezer arms will provide access to large and diverse synthetic receptor libraries.
- Loewik, Dennis W. P. M.,Weingarten, W. David,Broekema, Matthias,Brouwer, Arwin J.,Still, W. Clark,Liskamp, Rob M. J.
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p. 1846 - 1850
(2007/10/03)
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- A Very Mild, Catalytic and Versatile Procedure for α-Oxidation of Ketone Silyl Enol Ethers Using (salen)Manganese(III) Complexes; A New, Chiral Complex Giving Asymmetric Induction. A Possible Model for Selective Biochemical Oxidative Reactions Through Eno
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Facile, catalytic, selective (racemic and asymmetric) oxidation of ketone silyl enol ethers to give α-oxygenated products proceeds well under very mild, aprotic conditions using a racemic (salen)manganese(III) complex H2salen = bis(salicylidene)ethylened
- Reddy, D. Reddeppa,Thornton, Edward R.
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p. 172 - 173
(2007/10/02)
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