Daniel L. Comins, Xinghai Chen and Lawrence A. Morgan, "Enantiopure N-Acyldihydropyridones as Synthetic Intermediates: Asymmetric Synthesis of (-)-Septicine and (-)-Tylophorine," J.
Daniel L. Comins, Donald H. LaMunyon, and Xinghai Chen, "Enantiopure N-Acyldihydropyridones as Synthetic Intermediates: Asymmetric Synthesis of Indolizidine Alkaloids (-)-205A, (-)-207A, and (-)-235B," J.
Daniel L. Comins, Shenlin Huang, Cheryl L. McArdle and Charles L. Ingalls, "Enantiopure 2,3-Dihydro-4-pyridones as Synthetic Intermediates: A Concise Asymmetric Synthesis of (+)-Allopumiliotoxin 267A," Org.
Publications of Daniel L. Comins(Site not responding. Last check: 2007-10-08)
Daniel L. Comins, Xinghai Chen and Lawrence A. Morgan, "Enantiopure N -Acyldihydropyridones as Synthetic Intermediates: Asymmetric Synthesis of (-)-Septicine and (-)-Tylophorine," J.
Daniel L. Comins, Donald H. LaMunyon, and Xinghai Chen, "Enantiopure N -Acyldihydropyridones as Synthetic Intermediates: Asymmetric Synthesis of Indolizidine Alkaloids (-)-205A, (-)-207A, and (-)-235B," J.
Daniel L. Comins, Yue-mei Zhang and Sajan P. Joseph, "Enantiopure N -Acyldihydropyridones as Synthetic Intermediates: Asymmetric Synthesis of Benzomorphans," Org.
We have recently reported the synthesis of enantiopure 3-heterosubstituted pyrroline N-oxides of type 1 and 2 (Scheme 1) obtained by oxidation of the corresponding hydroxylamines, in turn available in large amounts from L-malic and L-aspartic acids, respectively.
This effect was rationalized on the basis of the stabilizing stereoelectronic effect provided by an adjacent electronegative group in the TS of the rate-determining step of the oxidation, from the nitrosonium cation to the final nitrone, which requires the removal of a proton, as indicated in Figure 1.
In this communication we report the application of nitrones 1 and 2 to the synthesis of enantiopure pyrrolizidines and structurally related compounds by means of 1,3-dipolar cycloaddition reactions to dimethyl maleate and -crotonolactone.
Synthesis of enantiopure pyrrolidine and piperidine derivatives(Site not responding. Last check: 2007-10-08)
Synthetic approaches to enantiopure 5- and 6-membered azaheterocycles have elicited a great deal of recent interest, because of their potential use as valuable intermediates for the synthesis of complex organic molecules.
Therefore, considerable attention has been focussed in recent years on the synthesis of enantiopure pyrrolidine and piperidine derivatives.
The origin of diastereoselectivity during the addition of allylsulfone, application of our protocol in the synthesis of natural products and further elaboration of our azaheterocycl- es to biologically important compounds will be presented.
E and E' represent the eutectic mixture composition where three phases (solid enantiopure proline, solid racemic compound, and liquid phase) exist in equilibrium.
The low solubility of proline means that the part of the diagram that is of interest for our solution phase system is located very near to the apex, and this portion is expanded in the main part of Fig.
Product enantioselectivities for aldol reactions carried out in aqueous media using these amino acid catalysts were also found to correlate well with the position of the eutectic, although yields and chemo- and enantioselectivities were in general lower (see Supplementary Information).
The research teams are currently in the process of producing and characterising a range of mutant enzymes (amino acid dehydrogenases) for use in the production of non-natural, commercially valuable enantiopure amino acids.
These enzymes will either be better suited for particular tasks or more versatile and therefore will enable the production of a much wider range of amino acids as novel synthons at a significantly reduced cost.
An alternative option for both synthesis and resolution of enantiopure amino acids is the use of an enzyme or biocatalyst.
Efficient Methodology for Synthesizing Enantiopure 6-Alkylpipecolic Acids(Site not responding. Last check: 2007-10-08)
Allkyl Substituent Effects on Pipecolyl Amide Isomer Equilibrium: Efficient Methodology for Synthesizing Enantiopure 6-Alkylpipecolic Acids and Conformational Analysis of Their N-Acetyl N’-Metylamides.
Our investigation has provided effective means for preparing novel alkylpipecolates and better understanding of their conformational effects in peptide structures.
Enantiopure 6-alkylpipecolates were synthesized by employment of α-tert-butyl N-(PhF) aspartate β-aldehyde in an aldol condensation, dehydration, reductive amination sequence.
Citebase - A simple entry into enantiopure hydrindanes, hydroisoquinolones and diquinanes from 3,10-dioxygenated ...(Site not responding. Last check: 2007-10-08)
Citebase - A simple entry into enantiopure hydrindanes, hydroisoquinolones and diquinanes from 3,10-dioxygenated dicyclopentadienes: Application to the synthesis of (+)coronafacic acid and a formal synthesis of (+)-coriolin
A simple entry into enantiopure hydrindanes, hydroisoquinolones and diquinanes from 3,10-dioxygenated dicyclopentadienes: Application to the synthesis of (+)coronafacic acid and a formal synthesis of (+)-coriolin
The hydroisoquinolones (+)-30 and (+)-33 can serve as useful enantiopure building blocks for the synthesis of complex indole alkaloids.
In the latter case, the substance, though chiral, might be racemic, or it might be partially racemic (i.e., an excess of one enantiomer over the other, but not to the exclusion of the minor enantiomer).
has been proposed for any non-racemic chiral compound, but it leaves out the question as to whether the compound is "enantiopure" (enantiomerically pure) or "enantioenriched" (having an excess of one enantiomer but not to the exclusion of the other).
In most cases, this term has been applied to a synthesis from a chiral, enantioenriched, or enantiopure starting material (sometimes said to belong to the "chiral pool," i.e., the inventory of readily available enantiopure or highly enantioenriched starting materials; "chiral pool" is another misnomer).
Min, Endy Yeo-Jung (2005-10-18) Kinetic resolution of chiral alpha-olefins using enantiopure Ziegler-Natta polymerization catalysts.
Towards the goal of kinetic resolution of chiral olefins, a series of enantiopure C1 symmetric metallocenes has been synthesized for use in the polymerization of chiral olefins.
The zirconocene dichloride (S)-6 has an enantiopure 2,2-dimethyl-3-pentyl ("ethylneopentyl") substituent on the "upper" cyclopentadienyl ligand.
The two that do form enantiopure conglomerates are R, and T. Curiously R wasn’t investigated in this study, and T performed quite poorly in generation of ee; a 100% ee of T was only able to generate a product with 58% ee.
Firstly, is the issue of enantiopure proline… since proline forms a 1:1 racemic mixture naturally, what’s the basis for starting with an enantiopure proline?
However, when one considers reality… ie: AA’s that actually form enantiopure conglomerates naturalistically, the results are not as encouraging.
In this thesis work we set our goals, as outlined in the chapter I, to synthesize enantiopure metal complexes or their assemblies with cavity of varying size and shapes.
As the resulting enantiopure complexes may find use in material science, enantiomer separation, chiral sensor or drug delivery, the synthetic procedure needed to be simple and efficient.
In order to synthesize cavity for a particular purpose in future we needed to understand the coordination chemistry of the complexes and the structural factors leading to the formation of the cavity.
is enantiopure 4,4’-bis(pyridyl)-1,1’-binaphthyl) and observed the first example of enantioselective luminescence sensing by a chiral metallocycle (Scheme II, JACS, 2002, 124, 4554).
Our successful synthesis of well-defined enantiopure 1,1’-binaphthyl-based oligomers and application of these oligomers in enantioselective fluorescence sensing were highlighted on the cover of Nov 1, 2002 issue of
“Well-Defined Enantiopure 1,1’-Binaphthyl-Based Oligomers: Synthesis, Structure, Photophysical Properties, and Chiral Sensing” Ma, L.; White, P.S.; Lin, W. Org.
New enantiopure atropisomeric aminoalcohols and their use in asimmetric catalysis
The compounds (S)-2a-c present some interesting features: (a) They can be easily obtained from optically pure 2,2’-bis(bromomethyl)-1,1’-binaphthalene (S)-3, a compound which became easily available from enantiopure 2,2’-dihydroxy-1,1’-binaphthalene only very recently.
This result is important from a practical point of view (a new class of efficient promoters is available) but also from a more speculative point of view: these compounds owe their chirality only to the atropisomerism of the binaphthyl nucleus and do not have any stereogenic carbon atom.
Our general objective is to develop methods to obtain significant yields of high-value compounds from biomass.
We are especially interested in developing routes to enantiomerically pure (enantiopure) chiral compounds since the value of many of these is very high and plant biomass should be a good source of these compounds since most of plant biomass is composed of enantiopure chiral units.
We are also interested in developing practical methods to concentrate organic compounds from dilute aqueous solutions such as those that result from anaerobic digestion.
Alibés, R.; Blanco, P.; de March, P.; Figueredo, M.; Font, J.; Álvarez-Larena, A.; Piniella, J. Synthesis and 1,3-dipolar cycloadditions of a new enantiopure cyclic nitrone"
de March, P.; Figueredo, M.; Font, J.; Raya, J.; Álvarez-Larena, A.; Piniella, J. Solid state and theoretical conformational analysis of enantiopure
de March, P.; Figueredo, M.; Font, J.; Medrano, J. Synthesis of new enantiopure monoketals of
