Oxidative Imination

Synthesis By Ring Enlargement from. vy/i-Benzene Oxide Imines... 

The initially obtained product undergoes isomerization and then the addition of phenyl azide to the phosphorus atom takes place. It is proposed that the oxidative imination does not depend on the steric effects of substituents. Actually, the interaction of 5-phenyl-2,4,6-triisopropyI-1,3,5-dioxaphosphorinane, existing as a mixture of three stereoisomers, gives with phenyl azide a mixture of three stereoisomers of 5-phenyl-5-phenylimino-2,4,6-triisopropyl-l,3,5-dioxaphosphorinane (83IZV2550). 

As the last point in Sect. IV, we discuss briefly the reactions of chiral sulfur compounds with electrophilic reagents. In contrast to nucleophilic substitution reactions, the number of known electrophilic reactions at sulfur is very small and practically limited to chiral tricoordinate sulfur compounds that on reacting with electrophilic reagents produce more stable tetracoordinate derivatives. It is generally assumed that the electrophilic attack is directed on the lone electron pair on sulfur and that the reaction is accompanied by retention of configuration. As typical examples of electrophilic reactions at tricoordinate sulfur, we mention oxidation, imination, alkylation, and halogenation. All these reactions were touched on in the section dealing with the synthesis of chiral tetracoordinate sulfur compounds. 

In general, sulfoximines are accessible by various routes, and most of them involve sulfur oxidation/imination sequences. For example, enantiopure 9 is commonly prepared starting from sulfide 10, which is oxidized with hydrogen peroxide (under acidic conditions) giving sulfoxide 11 (Scheme 2.1.1.1). Subsequent imina-tion of 11 with a mixture of sodium azide and sulfuric acid affords sulfoximine 9 as a racemate. Enantiomer resolution can then be achieved with camphorsul-fonic acid, leading to both enantiomers of 9 with high efficiency [15]. Alternatively, many sulfoximine syntheses start from enantiopure sulfoxides [16, 17], which can be stereospecifically iminated with 0-mesitylenesulfonylhydroxyl-amine (MSH) [18], as shown for the synthesis of sulfoximine (1 )-13 in Scheme 2.I.I.2. 

Oxidative imination of quinolinium salts and aza analogues with subsequent hydrolysis to cyclic amides occurs as in the pyridine series (85JHC765). 

Recent studies of polyaniline have been reviewed by McDiarmid et al. 179). They suggest that the polymer can exist in a wide range of structures, which can be regarded as copolymers of reduced (amine) and oxidized (imine) units of the form ... 

The oxidative imination of sulfides and sulfoxides via nitrene transfer processes leads to N-substituted sulfilimines and sulfoximines. This reaction is interesting as chiral sulfoximines are efficient chiral auxiliaries in asymmetric synthesis, a promising class of chiral ligands for asymmetric catalysis and key intermediates in the synthesis of pseudopeptides [169]. However, very few examples of such iron-catalyzed transformations have been described. 

Naphthyridine methiodide (43) underwent oxidative imination to 1-methyl-l,5-naphthyridin-2 (1 //)-imine hydriodide (44), accompanied by partial... 

Polymeric electrolytes, polymer-salt complexes, and gelled electrolytes, e.g., benzyl sulfonic acid siloxane, polyethylene oxide (imine, succinate)-LiC104, and PVDF gel in THF containing a mixture of Bu2Mg and AlEtCl2, respectively. 

Figure A15-5. Sertraliae hydrochloride oxidation, imine formation, and hydrolysis [12].

In 1975 Tamura et al. reported on the synthesis of two allyhc sulfoximines (25a and 25b) via oxidative imination using 0-mesitylenesulfonyl hydroxy-lamine (MSH) (Scheme 3) [11]. Both compounds are described as thermally stable, contrasting the behavior of the corresponding suMmines (Sect. 3.6, Type L). Interestingly, 4 years later Johnson et al. pointed out that sulfoximine 25c is readily subject to rearrangement and/or C - S bond heterolysis [12]. 

One entrance into the chemistry of sulfimide-based functional groups is electrophilic activation of the corresponding sulfoxides with triflic anhydride and subsequent reaction of the resulting sulfonium salts with trifluoromethane sulfonamide [39[ (Scheme 2.179). The other entrance is oxidative imination of a sulfoxide then trifluoromethanesulfonylation of the resulting imidosulfone [40]. 

Table 2. Bond Lengths (A) and Angles (J) in 1,2,3-Triazine Oxides, Imines and 1,2,3-Triazinium Salts...

Chemical Properties of Thiazolidines.—Alkylation of metal salts of thiazolidine-2-thione can yield either TV-alkyl derivatives, depending on the type of solvent, the alkylating agent, and the counter-ion e.g., the sodium salt with methyl iodide in dioxan gives mainly the 5-methyl compound, whilst with dimethyl sulphate in DMSO the N-methyl derivative is obtained. Oxidative imination of the thiazolidin-4-one (82), using Chloramine-T, gives (83) quantitatively, whilst... 

The TOP sequence can also be carried out in the presence of a heterogeneous reductant to effect an oxidation-imination-reduc-tion process leading from activated alcohols to amines (eqs 86 and 87). Polymer-supported cyanoborohydride (PSCBH) or sodium borohydride can be used as the reductant. The use of an oxidant and reductant in the same one-pot procedure is noteworthy. 

This transformation, proceeds via an in situ oxidation-imination-aldimine oxidation sequence. 

Addition of amines to aldehydes/ketones primary amine -1- mesityl oxide = acetone -1- imine separation of primary amine from secondary amines as the later has no reactivity for mesityl oxide imine can be hydrolysed back to primary [83]... 

Blackburn L, Taylor RJK (2001) In situ oxidation-imine formation-reduction routes from alcohols... 

The AgN03-catalyzed reactions of V-arylacrylamides with Ph2P(0)H or (EtO)2P(0)H afford the phosphorylated oxindoles in high yields (eq 26). Silver nitrate in combination with a chelating ligand efficiently catalyzes the oxidative imination of sulfoxides and sulfides with sulfonylamides and PhI(OAc)2- ... 

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