Building blocks, structural organization

Since our earlier review1 appeared not so long ago, it makes no sense to repeat here all facets of the radialene family. Therefore, we focus here on the synthesis and chemical transformation of the radialenes, and we suggest the reader consult our earlier review for information on structural and spectroscopic data as well as the use of radialenes as building blocks for organic conductors and organic ferromagnets, as these topics will not... 

Fig. 1.1. Molecular structures of some building blocks in organic conductors and superconductors...

This adopts a regular tetrahedron, and is the first structure that requires the third dimension, i.e. it is not a flat structure. The bond angle is about 109°. This is the fundamental building block of organic molecules. 

The etiolate of cyclopropanecarboxylic acid and its derivatives is an important building block for organic synthesis.However, the strained methylenecyclopropane structure of the enolate renders this species not only difficult to prepare, but also unstable. A rather simple method for the preparation of substituted 2-cyclopropylidene-5,5-dimethyl-l,3-dioxanes 15 is the thermolysis of the corresponding 2-alkylidenecyclopropanone acetals 14 which rearrange at 150 °C to the hydrolytically unstable ketene acetals. 

The catalysts used in alcohol synthesis hold the key to selectivity for methanol, for higher oxygenates, and to the control of hydrocarbon formation. Of interest are the mechanisms and the structure-function relationships in the catalysis of the C-H bond formation in reactions (1) and (2), C-C bond formation in reaction (5), and C-O bond formation in reactions (4), (6) and (7), as well as of reactions utilizing the synthesis intermediates as building blocks for organic syntheses such as amine (refs. 9-11) and aldol (refs. 12-14) syntheses. Further, the mechanistic roles of CO2 and water are of importance to understanding the... 

H. Maeda, Y. Ito, Y. Kusunose, T. Nakanishi, Dipyirolylpyrazoles anion receptors in protonated form and efficient building blocks for organized structures. Chem. Commun. 1136-1138 (2007)... 

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