Imine oximes

The carbonyl group forms a number of other very stable derivatives. They are less used as protective groups because of the greater difficulty involved in their removal. Such derivatives include cyanohydrins, hydrazones, imines, oximes, and semicarbazones. Enol ethers are used to protect one carbonyl group in a 1,2- or 1,3-dicarbonyl compound. 

Carb-16.5. Replacement of carbonyl oxygen by nitrogen (imines, oximes, hydrazones, osazones etc.)... 

This type of isomerism is also possible with other double bonds, such as C=N, N=N, or even C=S, though in these cases only two or three groups are connected to the double-bond atoms. In the case of imines, oximes, and other C=N compounds, if W = Y 60 may be called syn and 61 anti, though ( ) and (Z) are often used here too. In azo compounds there is no ambiguity. Compound 62 is always syn or (Z) regardless of the nature of W and Y, and 63 is E. 

This chapter, therefore, ends the monograph with a potpourri of reactions all of which occur without a change in oxidation state. In many cases, the reaction is one of nucleophilic attack at an electrophilic C-atom. The result is often hydrolytic bond cleavage (e.g., in carbohydrate conjugates, disubstitut-ed methylene and methine groups, imines, oximes, isocyanates, and nitriles, and various ring systems) or a nucleophilic substitution (e.g., hydrolytic de-halogenation of halocarbons and chloroplatin derivatives, and cyclization reactions). The formation of multiple bonds by dehydration is a special case to be discussed separately. 

Interest is mounting in this state, promoted once again by its possible implication in biological systems. Galactose oxidase, for example, is a copper enzyme which catalyses the oxidation of galactose to the corresponding aldehyde. The tervalent oxidation state may be prepared from Cu(II) by chemical, anodic and radical oxidation. Cu(III) complexes of peptides and macrocycles have been most studied, particularly from a mechanistic viewpoint. The oxidation of I" by Cu(III)-deprotonated peptide complexes and by imine-oxime complexes have a similar rate law... 

Additions of organometallics to the C=N bond of imines, oximes, hydrazones, and nitrones have been reviewed, with emphasis on the issues of reactivity and selectivity. Recent advances in enantioselective addition to imines of ketones are highlighted. 

Imines, Oximes, Hydrazones A -Me1hylbenzaldimine A -Phenylbenzaldimine Acetone oxime Benzaldehyde oxime Benzaldehyde A -phenylhydrazone... 

Four-coordinate neutral complexes with anionic ligands derived from deprotonated amines, imines, oximes and related ligands... 

The imine oximes (HYio 19) are Schiff bases of carbonyl oximes (14), and in their simplest forms these are also bidentate ligands,13 if Y is an alkyl or aryl group. 

Lithium salts of ketone derivatives such as imines, oximes and hydrazones have also been used for directed aldol reactions (Scheme 103).374 375 A recent example involves triple coordination of lithium in a very rigid transition state, to lead to regiospecificity in the product (Scheme 104).376... 

III. COMPOUNDS CONTAINING C=N DOUBLE BONDS A. Imines, Oximes and Hydrazones... 

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