Organic molecules chirality

P. Schreier, A. Bernreuther, and M. Huffer, Analysis of Chiral Organic Molecules, Walter de Gmyter Co., Berlin, Germany, 1995. 

The Rosetta mission with its planned landing on a comet, with analysis of cometary material (see Sect. 3.2), should provide more information on the occurrence of chiral molecular species in the cosmos (Adam, 2002). The GC-MS apparatus installed in the robotic lander RoLand is also able to separate and analyse chiral organic molecules (Thiemann and Meierhenrich, 2001). 

Nakazaki, M., The Synthesis and Stereochemistry of Chiral Organic Molecules with High Symmetry, 15, 199. 

Schreier, P., Bemreuther, A. and Huffier, M. (1995). Analysis of Chiral Organic Molecules. Methodology and Applications, Chapter 3. Walter de Gniyter, Berlin... 

A review of the older literature on compounds with a stereogenic axis is available22, as are reviews on planar chiral molecular structures 23, on the stereochemistry of twisted double bond systems 24, on helical molecules in organic chemistry 25, and on the synthesis and stereochemistry of chiral organic molecules with high symmetry 26. 

Schreier P, Bernreuther A, Huffer M (1995) Analysis of chiral organic molecules— methodology and applications, de Gruyter, Berlin... 

Solvent effects on the optical rotation of several conformationally rigid chiral organic molecules (fenchone, camphor, a- and /3-pinene, camphorquinone, verbenone and methy-... 

Several catalytic asymmetric approaches can be considered for the C-H to C-Het transformation demonstrated in Eq. (1), and the use of chiral Lewis acid-and chiral organic molecules has attracted considerable attention during recent years. 

Small chiral organic molecules may catalyze the asymmetric addition of ketones, and aldehydes to electron-deficient olefins, such as vinylidene acetones, nitroole-fins, enones, and vinyl sulfones. In this chapter we will describe the inter- and intramolecular reactions in which activation of the carbonyl compound takes place via enamine formation. 

Chiral organic molecules may promote conjugate additions in numerous ways (see also Chapters 3, 4 and 6). An important part of this chemistry is related to aminocatalytic reactions [5], that is, when activation takes place either via imi-nium intermediates (see Chapter 3) or, by activating the donors by forming enam-ines (this Chapter). 

An ideal approach to achieving chiral induction in a constrained medium such as zeolite would be to make use of a chiral medium. No zeolite that can accommodate organic molecules, currently exists in a stable chiral form. Though zeolite beta and titanosilicate ETS-10 have unstable chiral polymorphs, no pure enantiomorphous forms have been isolated. Although many other zeolites can, theoretically, exist in chiral forms (e.g., ZSM-5 and ZSM-11) none has been isolated in such a state. In the absence of readily available chiral zeolites, one is left with the choice of creating an asymmetric environment within zeolites by the adsorption of chiral organic molecules. 

Heterogeneous photochemical processes are concerned with the effect of light on interacting molecules and solid surfaces. The concept of photoinduced surface chemistry is commonly used to integrate these processes. As cited earlier, they involve surface phenomena such as adsorption, diffusion, chemical reaction and desorption [3]. Experiments and theoretical calculations make clear that the photochemical behavior of an adsorbed molecule can be very different from that of a molecule in the gas or liquid phase [4]. Photochemical reactions of this type involve molecules and systems of quite different complexity, from species composed of a few atoms in the stratosphere to large chiral organic molecules that presumably were formed in prebiotic systems. 

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