Enantioselective Synthesis of Near Enantiopure Compound by Asymmetric Autocatalysis Triggered by Asymmetric Photolysis with Circularly Polarized Light

2005 ◽  
Vol 127 (10) ◽  
pp. 3274-3275 ◽  
Author(s):  
Tsuneomi Kawasaki ◽  
Mirai Sato ◽  
Saori Ishiguro ◽  
Takahiro Saito ◽  
Yosuke Morishita ◽  
...  
Keyword(s):  
Polarized Light ◽  
Enantioselective Synthesis ◽  
Circularly Polarized Light ◽  
Circularly Polarized ◽  
Asymmetric Photolysis ◽  
Asymmetric Autocatalysis

scholarly journals Astronomical Sources of Circularly Polarized Light and Their Role in Determining Molecular Chirality on Earth

1985 ◽  
Vol 112 ◽  
pp. 171-175
Author(s):  
Ramon D. Wolstencroft
Keyword(s):  
Polarized Light ◽  
Racemic Mixture ◽  
Relative Importance ◽  
Chiral Molecules ◽  
Direct Sunlight ◽  
Primitive Earth ◽  
Circularly Polarized Light ◽  
Circularly Polarized ◽  
Chiral Selection ◽  
Asymmetric Photolysis

The major source of circularly polarized flux potentially capable of inducing asymmetric photolysis of a racemic mixture of chiral molecules on the primitive Earth is the daytime sky. The degree of circular polarization (q) depends on the slope and orientation of the local terrain which obscures part of the sky. After allowance for dilution by direct sunlight values of |q| range between about 10−4 and 10−5. The rates of (1) asymmetric photolysis, (2) chiral selection by the electro-weak process and (3) racemization are not yet well enough known for the relative importance of these processes to be definitely established.

scholarly journals Role of Asymmetric Autocatalysis in the Elucidation of Origins of Homochirality of Organic Compounds

Symmetry ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 694 ◽  
Author(s):  
Kenso Soai ◽  
Tsuneomi Kawasaki ◽  
Arimasa Matsumoto
Keyword(s):  
Organic Compounds ◽  
Enantiomeric Excess ◽  
Polarized Light ◽  
Circularly Polarized Light ◽  
Circularly Polarized ◽  
Asymmetric Autocatalysis ◽  
Chiral Crystals ◽  
Related Compounds ◽  
Origin Of Chirality

Pyrimidyl alkanol and related compounds were found to be asymmetric autocatalysts in the enantioselective addition of diisopropylzinc to pyrimidine-5-carbaldehyde and related aldehydes. In the asymmetric autocatalysis with amplification of enantiomeric excess (ee), the very low ee (ca. 0.00005%) of 2-alkynyl-5-pyrimidyl alkanol was significantly amplified to >99.5% ee with an increase in the amount. By using asymmetric autocatalysis with amplification of ee, several origins of homochirality have been examined. Circularly polarized light, chiral quartz, and chiral crystals formed from achiral organic compounds such as glycine and carbon (13C/12C), nitrogen (15N/14N), oxygen (18O/16O), and hydrogen (D/H) chiral isotopomers were found to act as the origin of chirality in asymmetric autocatalysis. And the spontaneous absolute asymmetric synthesis was also realized without the intervention of any chiral factor.

Differential polarization imaging of sickled cells

1988 ◽  
Vol 46 ◽  
pp. 62-63
Author(s):  
Marcos F. Maestre
Keyword(s):  
Optical Properties ◽  
Theoretical Approach ◽  
Polarized Light ◽  
Polarization Microscopy ◽  
Spectroscopic Techniques ◽  
Polarization Imaging ◽  
Circularly Polarized Light ◽  
Circularly Polarized ◽  
Microscopic Scale ◽  
Chiral Structures

Recently we have developed a form of polarization microscopy that forms images using optical properties that have previously been limited to macroscopic samples. This has given us a new window into the distribution of structure on a microscopic scale. We have coined the name differential polarization microscopy to identify the images obtained that are due to certain polarization dependent effects. Differential polarization microscopy has its origins in various spectroscopic techniques that have been used to study longer range structures in solution as well as solids. The differential scattering of circularly polarized light has been shown to be dependent on the long range chiral order, both theoretically and experimentally. The same theoretical approach was used to show that images due to differential scattering of circularly polarized light will give images dependent on chiral structures. With large helices (greater than the wavelength of light) the pitch and radius of the helix could be measured directly from these images.

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