Amination oxyamination

Another approach for the synthesis of networks relies on the polycondensation of multifunctionalized polyesters with the appropriate multifunctionalized agent, provided that one of the partner is at least tri-functionalized. Toward this end, several reaction have been reported, such as the Michael addition of amines onto acrylates [184], the coupling of ketones and oxyamines [185], the click copper(II)-catalyzed azide-alkyne cycloaddition [186], and esterification reactions [25, 159, 187]. Interestingly, if esterification reactions are used, the crosslinks are then degradable. 

Oxyamination.2 The reagent has been used to effect hydroxyamination of alkencs with aryl amines (equation I). The rearranged isomer 1 is the major product with terminal alkenes (R3 = R4 = H). 

Methyl-l,3-diselenonylidene)piperidinium perchlorate, 3168 (9-Methyl-/V,/V-disilyl hydroxyl amine, 0513 Methylenebis(nitramine), 0481 Methylenebis(3-nitramino-4-methylfurazan), 2801 Methylenebis(oxyamine), 0502b... 

The chloramine derivatives (ArS02NClNa) of a variety of other aryl-sulfonamides (Ar = phenyl, o-tolyl, p-chlorophenyl,/>-nitrophenyl, and o-carboalkoxyphenyl) have been used successfully in these catalytic oxy-aminations. Since only chloramine-T (Ar = p-tolyl) and chloramine-B (Ar = phenyl) are commercially available, we have developed a convenient procedure for generating the chloramines in situ for use in the modification involving phase-transfer catalysis. One simply stirs a suspension of the arylsulfonamide with an equivalent of sodium hypochlorite (Clorox) until a homogeneous solution is obtained. When this solution is used in the PTC method (see Ref. 2 for experimental details), the yields of oxyaminated product are comparable with those obtained with isolated chloramine salts. 

The complexes will effect oxyamination reaction with alkenes in a stereospecific reaction (Scheme 8).290 After reductive cleavage of the intermediate alkanolaminato complex (I) (see below) vicinal amino alcohols (II) are formed. The reaction is unusual in that the new C—N bond is always formed at the least substituted terminal alkenic carbon atom, and there is a clear preference for the imido complex to use its NR group for coordination to the osmium despite the steric restraints of R.299,300 However, the least sterically hindered part of the alkene moiety is attached to. the nitrogen atom.290,291,300 The yields of amino alcohols in the reaction can be improved by addition of tertiary alkyl bulkhead amines (see below). 

The chloro nitroso adducts of the ( -protected glycals were converted, via the intermediate oximes, to 2-amino-2-deoxy sugars48,50,53,59 the overall oxyamination of glycals is hence accomplished. Amines of the opposite configuration are prepared depending on the method of reduction. The chloro nitroso adducts can be directly treated with zinc-copper couple in acetic acid, or can be first converted to fully acetylated oximes which are then catalytically hydrogenated. 

The relative stereochemistry of the newly formed stereogenic centers attained in the aminometa-lation reaction of 1,2-disubstituted alkenes is lost if the / -aminoalkylpalladium complex is allowed to undergo /J-hydride elimination to give enamines, or if a successive reduction step is performed, unless a stereocenter is initially present in the alkene or in the amine. However, the C —Pd bond can be functionalized to achieve overall oxyamination, diamination, aziridination, aminocarbonylation, and carboamination reactions13,14. 

Vicinal diamines, e.g., 5, were formed as byproducts in the oxyamination of terminal alkenes with excess amine and lead tetraacetate, but were exclusively obtained when the oxidant is bromine, 3-chloroperoxybenzoic acid, or, V-bromosuccinimide64. 

When chiral amines are used in the oxyamination reaction, stereogenicity is induced in the amination step and in this way optically active amino alcohols are obtained after oxidation69. An optically active secondary or tertiary amine can be used as a ligand for palladium in the intermediate 7t-complex, to which an excess of an achiral amine can be added (reagent-induced diastereoselectivity). Here, a pair of diastereomeric tt-complexes are formed which may be in equilibrium with each other, the degree of asymmetric induction is dependent on the ratio between the diastereomeric complexes and/or on their different reactivity. 

The oxyamination and diamination procedures described so far suffer from two important limitations. They require a stoichiometric quantity of osmium reagents and it is difficult to remove the tert-alkyl group from the product. Hence, procedures that employ catalytic amounts of osmium tetroxide for the preparation of vicinal hydroxy 4-methylbenzenesulfon-amides, precursors of /1-hydroxy amines, have been developed. 

Oxyamination. The ratio of amino alcohol to diol formed by reaction of alkenes with the reagent is considerably improved by the presence of tertiary alkyl bridgehead amines. Of these ligands, quinuclidine (1, 976 4, 417) is the most efficient. In this case DME is used in place of pyridine as solvent. 

Sharpless and coworkers have reported a new series of reagents for allylic amination of olefins,79-5 vicinal oxyamination of olefins,76 and 1,2-diamination of 1,3-dienes.77... 

Oxyamination of the 5-(trifluoromethyl)dithiatriazine la with bis(trifluoromethyl)amine 2V-ox-ide gives aminooxy-substituted dithiatriazines 6 following a radical mechanism.14... 

The post-synthetic methodology has also been used to incorporate catalytic centres. The incorporation of chiral l,l -bi-2-naphthols (BINOLs) into CMPs has been used to perform catalytic reactions using the alcohol groups to bind to catalytically active centres such as phosphoric acids for asymmetric transfer hydrogenations or titanium for diethyl-zinc additions. Other metal-containing functionalities have also been incorporated into CMP networks. The coordination of metals to pyridine or phenylpyridine via Sonogashira reactions has also been reported for catal5Aic transformations such as reductive amination or aza-Henry reactions, a-atylations and oxyaminations. ... 

The palladium-catalysed oxyamination of olefins is well known, and it has now been found that, by the use of chiral reagents, asymmetry can be induced in the amination step and that optically active tertiary amino-alcohols result. 1-Piperidino-l-trimethylsilyloxycyclopropane and the corresponding 1-hydroxy-compound have been prepared and examined for their utility as cyclopropanone equivalents. ... 

Oxyamination. Efficient oxyamination of st)Tene derivatives with oxaziridines was described using copper(II) chloride as a catalyst. The corresponding aminals were obtained in moderate to good yields (eq 36). 

Following the report last year of the first vicinal oxyamination of olefins using aminated derivatives of osmium tetroxide. Sharpless has extended this analogy to oxidations involving selenium dioxide. Two aza analogues of selenium dioxide have been prepared by either the reaction of selenium tetrachloride with the amine or... 

Diphenyl sulphide reacts with anhydrous chloramine-T to give an adduct (8), which is a useful reagent for the amination of olefins (Scheme 7). The osmium-catalysed oxyamination of olefins by chloramine-T has been improved by phase-transfer catalysis, and the stereospecific vicinal oxyamination of olefins by alkylimido-osmium compounds has been reported. ... 

---