Carl Friedrich Naumann and the introduction of enantio terminology: A review and analysis on the 150th anniversary

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103

Nearly a decade after discovering molecular chirality in 1848, Louis Pasteur changed research direction and began investigating fermentations. Conflicting explanations have been given for this switch to microbiology, but the evidence strongly suggests that Pasteur's appointment in 1854 to the University of Lille--an agricultural-industrial region where fermentation-based manufacturing was of great importance--and an appeal for help in 1856 by a local manufacturer experiencing problems in his beetroot-fermentation-based alcohol production played a significant role. Thus began, in late 1856, Pasteur's pioneering studies of lactic and alcoholic fermentations. In 1857, reportedly as a result of a laboratory mishap, he found that in incubations of ammonium (+/-)-tartrate with unidentified microorganisms (+)-tartaric acid was consumed with considerable preference over (-)-tartaric acid. In 1860, he demonstrated a similar enantioselectivity in the metabolism of tartaric acid by Penicillium glaucum, a common mold. Chance likely played a significant role both in Pasteur's shift to microbiology and his discovery of enantioselective tartrate fermentations, but he rejected pure serendipity as a significant factor in experimental science and in his own career. Pasteur's milestone discovery of biological enantioselectivity began the process that in the long run established the fundamental importance of molecular chirality in biology.

Section: ''Memoir On the Fermentation Of Tartaric Acid''mentioning

confidence: 99%

The discovery of biological enantioselectivity: Louis Pasteur and the fermentation of tartaric acid, 1857—A review and analysis 150 yr later

Gál

2007

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103

“…The former refers to the relationship between two nonsuperposable mirror-image objects, while chirality denotes the phenomenon that indicates the existence of such objects. 7 In the light of this observation, expressions like chiral synthesis, chiral reaction, or chiral transformation are extremely confusing as only a careful reading reveals the meaning intended by the authors; formation of a single chiral stereoisomer or, of various molecules that are chiral but they may or may not be enantiomers.…”

Section: Chirality and Discriminationmentioning

confidence: 99%

Chirality and chemical processes: A few afterthoughts

Cintas¹

2007

Chirality and chiral have become terms that pervade a wide range of disciplines in physical and life sciences. Although such terms are precisely defined, their use often engenders confusion and ambiguity. Perhaps, the most improper use of chirality, yet widely accepted, is related to its association with stereodynamics and physico-chemical transformations, such as chiral discrimination, chiral resolution, chiral recognition, chiral synthesis, and so on. Even though this conceptual perversion has been highlighted by renowned stereochemists, it has become a recurring keyword and a hot message in modern literature. It is timely to renew the correct use and context in forums such as the present journal, adding further reflections that may help both beginners and practitioners. This short article is not intended to criticize or highlight errors, but rather to encourage a level of rigor and the use of statements, which should be universally correct.

“…The misuse of scientific language provides additional motivation for its study. A great deal of discussion of problems associated with the use of stereochemical language has appeared6–14 and one can deduce from these discussions that two different types of problems exist. One encompasses problems arising from fundamental conceptual issues, e.g., perceived or real “incorrect” definitions of terms; changes in the meaning or connotation of terms arising from obsolescence or new technological developments; ignoring context in applying terminology; lack of appreciation of the intrinsic nature of chirality and its relationship to stereoisomerism; etc., and Mislow14 has given an incisive analysis of these matters.…”

Section: Introductionmentioning

confidence: 99%

Louis Pasteur, language, and molecular chirality. I. Background and Dissymmetry

Gál

2010

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Louis Pasteur resolved sodium ammonium (±)-tartrate in 1848, thereby discovering molecular chirality. Although hindered by the primitive state of organic chemistry, he introduced new terminology and nomenclature for his new science of molecular and crystal chirality. He was well prepared for this task by his rigorous education and innate abilities, and his linguistic achievements eventually earned him membership in the supreme institution for the French language, the Académie française. Dissymmetry had been in use in French from the early 1820s for disruption or absence of symmetry or for dissimilarity or difference in appearance between two objects, and Pasteur initially used it in the latter connotation, without any reference to handedness or enantiomorphism. Soon, however, he adopted it in the meaning of chirality. Asymmetry had been in use in French since 1691 but Pasteur ignored it in favor of dissymmetry. The two terms are not synonymous but it is not clear whether Pasteur recognized this difference in choosing the former over the latter. However, much of the literature mistranslates his dissymmetry as asymmetry. Twenty years before Pasteur the British polymath John Herschel proposed that optical rotation in the noncrystalline state is due to the "unsymmetrical" [his term] nature of the molecules and later used dissymmetrical for handed. Chirality, coined by Lord Kelvin in 1894 and introduced into chemistry by Mislow in 1962, has nearly completely replaced dissymmetry in the meaning of handedness, but the use of dissymmetry continues today in other contexts for lack of symmetry, reduction of symmetry, or dissimilarity.