Organic chemistry molecular chirality

In Chapter 4, on molecular symmetry, 1 have added two new sections. One of these concerns the relationship between symmetry and chirality, which is of great importance in synthetic organic chemistry. The other relates to the connection between the symmetry of a molecule and whether it has a permanent dipole moment. 

Adam, W., Lazarus, M., Boss, B. et al. (1997) Enzymic resolution of chiral 2-hydroxy carboxylic acids by enantioselective oxidation with molecular oxygen catalyzed by the glycolate oxidase from spinach (Spinacia oleracea). The Journal of Organic Chemistry, 62 (22), 7841-7843. 

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. 

Biology and organic chemistry are replete with examples of self-assembly. Examples include lipid bilayers, the DNA duplex, proteins in their correctly folded forms, self-assembled monolayers, and crystals. In MESA, we extend ideas abstracted from molecular recognition - shape recognition, chirality, directional interactions, hierarchy of bonds, and hydrophobicity - to the mesoscale. 

One of the advantages of supramolecular chemistry over the covalent molecular approach resides in the possibility of inducing and/or transferring properties from singular molecules to self-organized multi-molecular assemblies. Chirality is one of these properties it stems from the electronic level (the helical nature of the electron rearrangement during a transition in chiral chromophores) and spreads up to the three-dimensional spatial disposition of atoms, or molecular components in molecular or supramolecular entities, respectively. 

Solid-supported synthesis has rapidly emerged as an important strategy in synthetic organic chemistry. Solid-phase methodology is aimed at the direct synthesis of libraries of molecularly diverse compounds for biological evaluation in lead discovery. The asymmetric addition of polymer-supported chiral crotylsilanes to acetals and allylation of polymer-bound acetals linked through an ester with the chiral crotylsilanes has been investigated [44d] la can be employed in these crotylation reactions and results in the formation of polymer-supported homoallylic esters with diastereoselec-tivity similar to that of solution-phase reactions. 

Enantiomers are compounds which have the same chemical structure but different conformations, whose molecular structures are not superimposable on their mirror images, and, because of their molecular asymmetry, these compounds are optically active. The most common cause of optical activity is the presence of one or more chiral centers which, in organic chemistry, are usually related to tetrahedral structures formed by four different groups around carbon, silicon, tin, nitrogen, phosphorus, or sulfur. 

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