Journal ArticleDOI
Asymmetric autocatalysis triggered by carbon isotope (13C/12C) chirality.
TLDR
It is demonstrated that the sense of enantioselection in this system can be influenced by a factor as subtle as chirality in an alcohol that arises only because two positions differ in having 12C and 13C atoms, which can be amplified to an easily seen experimental outcome using asymmetric autocatalysis.Abstract:
Many apparently achiral organic molecules on Earth may be chiral because of random substitution of the 1.11% naturally abundant 13C for 12C in an enantiotopic moiety within the structure. However, chirality from this source is experimentally difficult to discern because of the very small difference between 13C and 12C. We have demonstrated that this small difference can be amplified to an easily seen experimental outcome using asymmetric autocatalysis. In the reaction between pyrimidine-5-carbaldehyde and diisopropylzinc, addition of chiral molecules in large enantiomeric excess that are, however, chiral only by virtue of isotope substitution causes a slight enantiomeric excess in the zinc alkoxide of the produced pyrimidyl alkanol. Asymmetric autocatalysis then leads to pyrimidyl alcohol with a large enantiomeric excess. The sense of enantiomeric excess of the product alcohol varies consistently with the sense of the excess enantiomer of the carbon isotopically chiral compound.read more
Citations
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Trifluoromethyltrimethylsilane: nucleophilic trifluoromethylation and beyond.
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Prebiotic systems chemistry: new perspectives for the origins of life.
TL;DR: This paper presents a probabilistic analysis of the stationary phase replacement of Na6(CO3)(SO4)/ Na2SO4 in horseshoe clusters and shows clear trends in the number of stationary phases and in the stationary phases of Na2CO3.
Journal ArticleDOI
Deuterium- and Tritium-Labelled Compounds: Applications in the Life Sciences
TL;DR: Advances in the application of hydrogen isotopes in the life sciences are described and 3 H, in particular, has seen an increase in utilization, especially in pharmaceutical drug discovery.
Journal ArticleDOI
Greatly Increased Toughness of Infiltrated Spider Silk
Seung-Mo Lee,Eckhard Pippel,Ulrich Gösele,Christian Dresbach,Yong Qin,C. Vinod Chandran,Thomas Bräuniger,Gerd Hause,Mato Knez +8 more
TL;DR: It is demonstrated that metals can be intentionally infiltrated into inner protein structures of biomaterials through multiple pulsed vapor-phase infiltration performed with equipment conventionally used for atomic layer deposition (ALD).
Journal ArticleDOI
The Origin of Biological Homochirality
TL;DR: The single-handedness of biological molecules has fascinated scientists and laymen alike since Pasteur's first painstaking separation of the enantiomorphic crystals of a tartrate salt more than 150 yr ago.
References
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PatentDOI
First practical method for asymmetric epoxidation
Tsutomu Katsuki,K. B. Sharpless +1 more
TL;DR: In this article, a metal alkoxide is used as a catalyst, where the metal has a coordination number of at least four, and at least one, usually two, of the alkoxide groups bonded to the metal are bonded to asymmetric carbon atoms.
Journal ArticleDOI
Enantioselective addition of organozinc reagents to aldehydes
Kenso Soai,Seiji Niwa +1 more
Book ChapterDOI
[4] Circular dichroism
TL;DR: Circular dichroism is a spectroscopic method which depends on the fact that certain molecules interact differently with right and left circularly polarized light and can provide information about the secondary structure of proteins and nucleic acids and about the binding of ligands to these types of macromolecule.
Journal ArticleDOI
Asymmetric autocatalysis and amplification of enantiomeric excess of a chiral molecule
TL;DR: In this paper, it was shown that autocatalysis in a chemical reaction can indeed enhance a small initial enantiomeric excess of a chiral molecule, and that the resulting chirality imbalance can become overwhelming.
Journal ArticleDOI
Enantiomeric Excesses in Meteoritic Amino Acids
John R. Cronin,Sandra Pizzarello +1 more
TL;DR: Gas chromatographic-mass spectral analyses of the four stereoisomers of 2-amino-2,3-dimethylpentanoic acid obtained from the Murchison meteorite show that the L enantiomer occurs in excess, indicative of an asymmetric influence on organic chemical evolution before the origin of life.