Ring compounds, large, synthesis

This reaction is used in the synthesis of large-ring compounds. 

A spectacular application of the acyloin ester condensation was the preparation of catenaries like 11. These were prepared by a statistical synthesis which means that an acyloin reaction of the diester 10 has been carried out in the presence of an excess of a large ring compound such as 9, with the hope that some diester molecules would be threaded through a ring, and would then undergo ring closure to give the catena compound ... 

Non-Benzenoid Aromatic Compounds.—The synthesis of aromatic molecules containing small, medium, and large rings, using the reaction of dicarbonyl compounds and bis-ylides, has been thoroughly reviewed.95... 

This interesting reaction is especially useful for the synthesis of medium- and large-ring compounds from dicarboxylic esters, and is effective for ring sizes that cannot be made by the Dieckmann condensation or decarboxylation (Section 18-1 OB). Radical anions formed by addition of sodium to the ester... 

Metallacycloalkanes - Synthesis, Structure and Reactivity of Medium to Large Ring Compounds... 

Owing to the realisation of the importance of medium to large metallacycles in selective catalytic oligomerisation processes, particularly ethylene trimerisation and tetramerisation, we envisage that the field of metallacycloalkanes will be a significant growth area. Clearly new routes will have to be devised for the synthesis of metallacycloheptane, -octane and -nonanes so that these novel ring compounds can be efficiently prepared and studied. 

Griesbeck, A.G., Henz, A., Kramer, W., Lex, J., Nerowski, F., and Oelgemoller, M. (1997) Synthesis of medium- and large-ring compounds initiated by photochemical decarboxylation of W-phthalimidoalkanoates. Helvetica Chimica Acta, 80, 912-933. 

Ketene, dichloroketene, and related compounds react with allylic ethers, sulfides, and selenides in a [3.3] sigmatropic rearrangement. This interesting reaction allows the synthesis of a number of medium and large ring compounds by expansion [72] [73] [74]. Dichloroketene has been prepared in situ by slow addi-... 

The syntheses of crown compounds invariably rely upon the Williamson ether synthesis, a dated but reliable reaction which is extemely useful in the synthesis of these medium-ring and large-ring compounds.7 The syntheses are usually not discussed in much detail in the literature, since the emphasis in the general area of supramolecular chemistry is on the properties of the target compounds, not on their preparation. It is frequently the case, however, that these apparently conventional syntheses are far from straightforward. 

In contrast to the pyrazoles, there is no single method of wide application for the synthesis of imidazoles, although the use of o-phenylenediamine and related compounds in benzimidazole synthesis might merit such a description. The common synthetic methods are divided into those which build up the imidazole ring from largely acyclic precursors, and transformations of other heterocyclic species. Ring-synthetic procedures can entail the formation of between one and four bonds. 

The radical cyclization methodology was relatively under-explored for the synthesis of medium ring compounds compared to that of five- and six-membered and large ring compounds [28, 29]. Construction of seven-membered rings employing radical... 

Much of the photochemistry carried out on the cyclic sulphones has had a leaning towards the synthesis of novel and strained compounds. The compounds studied range from three-membered ring species up to large ring compounds and the material will be treated in this sequential manner. The photochemistry of these compounds and others has been reviewed recently72. 

Macrolide A large-ring compound, such as erythromycin, that is antibacterial by affecting protein synthesis. 

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