Version 1
: Received: 4 July 2023 / Approved: 5 July 2023 / Online: 5 July 2023 (11:23:21 CEST)
How to cite:
Zhu, H.; Jia, Y.; Li, Z.; Zhu, Y.; Pittman, Jr, C. Amplification of Enantiomeric Excess without Any Chiral Source in Prebiotic Case. Preprints2023, 2023070287. https://doi.org/10.20944/preprints202307.0287.v1
Zhu, H.; Jia, Y.; Li, Z.; Zhu, Y.; Pittman, Jr, C. Amplification of Enantiomeric Excess without Any Chiral Source in Prebiotic Case. Preprints 2023, 2023070287. https://doi.org/10.20944/preprints202307.0287.v1
Zhu, H.; Jia, Y.; Li, Z.; Zhu, Y.; Pittman, Jr, C. Amplification of Enantiomeric Excess without Any Chiral Source in Prebiotic Case. Preprints2023, 2023070287. https://doi.org/10.20944/preprints202307.0287.v1
APA Style
Zhu, H., Jia, Y., Li, Z., Zhu, Y., & Pittman, Jr, C. (2023). Amplification of Enantiomeric Excess without Any Chiral Source in Prebiotic Case. Preprints. https://doi.org/10.20944/preprints202307.0287.v1
Chicago/Turabian Style
Zhu, H., Yujun Zhu and Charles Pittman, Jr. 2023 "Amplification of Enantiomeric Excess without Any Chiral Source in Prebiotic Case" Preprints. https://doi.org/10.20944/preprints202307.0287.v1
Abstract
A general method is presented that permits enantiomers, originally present in a low enantiomeric excess (%ee1), to accumulate in a high %ee (%ee2) without a chiral source present. An equation was derived that demonstrates the final %ee2 of any unreacted chiral starting material will become higher when that starting material has reacted to generate an additional chiral center, hence forming two sets of diastereomeric enantiomeric products. Importantly, chiral amplification factor (multiples), %ee2/%ee1, depends on the yield of this reaction (p), which exhibits a nonlinear increase in amplification as p approaches 100%. This process is inevitable. It represents a possible route by which small initial %ee1 values of prebiotic molecules could have been raised to high %ee2 contents during the pre-evolution of life period on Earth, without the need for an added chiral source to be present. This predicted behavior was then experimentally verified in Pictet-Spengler reactions of L-tryptophane methyl ester (L-TME) samples present in low enantiomeric excess (%ee1) with biacetyl or oxaldehyde (model reactions) run to various yields. Each reaction generates stereoisomer products, and chiral amplification of the L-TME’s initial %ee1 values to higher %ee2 values occurs in the unreacted (recovered) L-TME. Repeated cycles of these reactions create very high L-TME %ee values. Self-cyclodimerization of low %ee1 L-amino acids with their D-enantiomers to generate L,L-, D,D- and L,D-cyclic products were computationally studied, leading to the same conclusion. Small %ee1 values are enhanced to larger %ee2 in the unreacted starting materials.
Chemistry and Materials Science, Organic Chemistry
Copyright:
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
