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Current Organic Chemistry

Editor-in-Chief

ISSN (Print): 1385-2728
ISSN (Online): 1875-5348

Review Article

Paradoxes of Symmetry: Homochirality; Cryptochiral Reactions; Chiral Field, Memory, and Induction; Chiral and Racemic Environment

Author(s): Valerii A. Pavlov and Tatiana N. Pavlova

Volume 21, Issue 10, 2017

Page: [872 - 888] Pages: 17

DOI: 10.2174/1385272821666161128115134

Price: $65

Abstract

A new concept is proposed on the basis of chemical, biological and physical data, according to which stable chiral factors on the prebiotic Earth are likely to contribute to homochirality arising (configurational homogeneity of important compounds of life). The axial rotation of the Earth near Moon (and Sun) and orbital movement of the Earth-Moon double planet around the Sun produces the simplest and most stable chiral effect in the terrestrial conditions. This right-handed helix motion is considered as the basis for Nature’s selection of L amino acids and D sugars for the synthesis of right-handed helices of essential macromolecules of living matter. This stage may be a rate-determining step of life origin. Lunar tides could be a possible “intermediate link” of the environment chiral influence on the molecular level. The surf occurring at an angle to the plane of spin rotation of the Eath leads to the predominant formation of right-handed helix-shaped water associates. Biological evidence of their existence is discussed. These chiral water associates could contribute to the preferential synthesis of homochiral molecules of amino acids and sugars. Their inclusion to the right-handed helical structure protects these molecules from racemization. Only a very small energy barrier exists between enantiomers, therefore the chiral field of the environment can affect asymmetric reactions and chiral processes in terrestrial conditions. The problem of chiral effects in polymerization, catalytic reactions with chirality amplification (chiral autcatalysis), cryptochiral and dissolution-recrystallization reactions are discussed. The chiral field, memory, and asymmetric induction phenomena are also considered. Because physical properties of racemic compounds change significantly in comparison with enantiomeres, it would be difficult, if not impossible, to explain the distinctions between racemates and enatiomers in the crystalline or dissolved forms only by dissimilar hydrogen bonding. This issue is discussed in the light of the possible influence of the external chiral field. The consideration of this effect may be beneficial for the understading of the mechanism of nonlinear chiral catalytic reactions. The concept of the external chiral field can be useful also for the explanation of other biological artifacts. Aspects of a possible chiral or racemic external influence on these reactions, effects, and processes are discussed. It is likely that this influence is more significant than believed.

Keywords: Homochirality, macromolecular helices, chiral amplification, chiral and racemic fields.

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