Large rings, reviews

As a class of compounds, nitriles have broad commercial utility that includes their use as solvents, feedstocks, pharmaceuticals, catalysts, and pesticides. The versatile reactivity of organonitnles arises both from the reactivity of the C=N bond, and from the abiHty of the cyano substituent to activate adjacent bonds, especially C—H bonds. Nitriles can be used to prepare amines, amides, amidines, carboxyHc acids and esters, aldehydes, ketones, large-ring cycHc ketones, imines, heterocycles, orthoesters, and other compounds. Some of the more common transformations involve hydrolysis or alcoholysis to produce amides, acids and esters, and hydrogenation to produce amines, which are intermediates for the production of polyurethanes and polyamides. An extensive review on hydrogenation of nitriles has been recendy pubHshed (10). 

In general, the methods of synthesis and reactions of oxiranes and thiiranes fused to ordinary or large rings are not particularly affected by the ring fusion. The reader is referred to Chapters 5.05 and 5.06, and reviews cited there, many of which include fused-ring examples. 

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... 

A review of the stabilities and catalytic properties of binuclear metal complexes of large-ring N,0 macrocycles concentrates on the iron(II) and iron(III) complexes of (184) and (185). ... 

The Dimroth rearrangement has been observed for many other rings including six-membered rings. Reviewing this large field, D. J. Brown concluded that two properties of R drive the equilibrium 49 50 to the right ... 

Reviews of general interest in this area highlights microreactors that can be used for a variety of photochemical reactions such as the synthesis of large ring ketones. Interest in the control that can be exercised on the outcome of photochemical reactions in constrained environments continues to increase and reviews dealing with the enantioselective photoreactions of achiral compounds in chiral crystals and inclusion crystals have been published. ... 

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. 

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