VICINAL OXYAMINATION OLEFINS

OSMIUM-CATALYZED VICINAL OXYAMINATION OF OLEFINS BY CHLORAMINE-T cis-2-(p-TOLUENESULFONAMIDO)CYCLOHEXANOL AND 2-METHYL-3-(p-TOLUENESULFONAMIDO)-2-PENTANOL... 

OSMIUM-CATALYZED VICINAL OXYAMINATION OF OLEFINS BY JV-CHLORO-A-ARGENTOCARBAMATES ETHYL threo-l 1 (2-HYDROX Y-l, 2-DIPHENYI,-ETHYL)]CARBAMATE... 

OSMIUM-CATALYZED VICINAL OXYAMINATION OF OLEFINS BY Af-CHLORO-jV-ARGENTOCARBAMATES ETHYL fArco-[l-(2.HYDROXY-l,2-DIPHENYL-ETHYDICARBAMATE... 

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... 

Oxyanunation. Vicinal oxyamination of olefins can be carried out with OSO4 in catalytic amounts with this N-chloro-N-argentocarbamate (c/. Osmium tetroxide-Chloramine-T, 7, 256). A major improvement over chloroamine-T is that the —COOCfCHaja group is readily eliminated. 

Improved procedures for osmium-catalysed vicinal oxyamination of olefins by JV-chlorosodiocarbamates-Hg(N03)2-Et4NOAc are recommended especially for trisubstituted systems. Asymmetric induction in the reaction of OSO4 with olefins using dihydroquinidine acetate in up to 83% e.e. is now possible. "... 

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. ... 

Nitrogen-transfer reactions of osmium imido species lead to cis diamines or amino alcohols. Reaction of 0s02(N-/-C4H9)2 [63174-13-0] with olefins produces vicinal diamines after reductive cleavage. Catalytic oxyamination of olefins using chloramine-T or AJ-chlor-AJ-argenocarbamates yields vicinal hydroxy toluenesulfonamides (112) or carbamates (113), respectively, which maybe deprotected to vicinal amino alcohols. 

An interesting offshoot of the work on osmium-catalyzed dihydroxylations is vicinal hydroxyamination [24]. Here, imido analogs of OSO4 react with olefins to produce /5-aminoalcohols by a cw-addition process. The oxyamination reaction can be made catalytic in OSO4 by employing chloramine salts of arylsulfonamides (ArS02NClNa) or carbamates. 

Oxyamination of olefins. This reagent reacts with a variety of olefins to give, after reductive cleavage of intermediate osmate esters, cis-vicinal amino alcohols in fair to high yield. The reaction is regiospecific in that the new C—N bond is formed at the least substituted carbon atom of the olefin. The reagent reacts more rapidly with monosubstituted olefins than with di- and trisubstituted olefins. Diols are obtained as the main products from hindered olefins. Methylene chloride or THF can be used as solvents, but pyridine is the solvent of choice. 

Improvements in the osmium-catalysed hydroxylation and oxyamination of olefins continue to appear." In the vicinal hydroxylation of olefins by t-butyl hydroperoxide earlier methods involved rather alkaline conditions, but this drawback has been overcome by using Et4NOAc instead of Et4NOH and changing the solvent from t-butyl alcohol to acetone."" Although the new method works well for base-sensitive compounds (e.g. esters), it fails with tetrasubstituted olefins. Yields are generally around 70%. Vicinal hydroxy-toluene-p-sulphonamides (8),... 

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