Osmium tetroxide and sodium periodate

Pc with osmium tetroxide and sodium periodate, and subsequent 1,3-dipolar cycloaddition of the azomethine ylide, formed in the presence of an excess of sarco-sine, and Cgo to give the fulleropyrrolidine-Pc conjugate 17. The second protocol relies on the fulleropyrrolidine formation prior to the statistical cyclotetrameriza-tion with 4-tert-bu tv I p It lit a lonitrile. The low yields obtained via the latter strategy are presumably a result of the steric congestion of the benzodinitrile-functionalized fullerene precursor in the statistical crossover condensation. 

The rest of the synthesis (Scheme 13) is completely stereospecific and most of the steps are known (20). The bicyclic acid was oxidatively decarboxylated with lead tetraacetate and copper acetate (21). The resulting enone was alkylated with methyllithium giving a single crystalline allylic tertiary alcohol. This compound was cleaved with osmium tetroxide and sodium periodate. Inverse addition of the Wittig reagent effected methylenation in 85% yield. Finally, the acid was reduced with lithium aluminum hydride to grandisol. 

The 4-styryl products are of value in that they offer an alternative route to imidazole-4-carbaldchydes when they are oxidized by osmium tetroxide and sodium periodate in about 70% yield [20]. 

Gallc er and co-workers devised a formal enantioselective synthesis of ( — )-3 in wduch the stereogenic center at C-6 was derived fiom Cbz-protected (S)-2-amino-4-pentenoic acid (36) (44). Acylation of 3,3-dimethoxy-pyrrolidine (37) with this acid yielded amide 38, which was converted into aldehyde 39 by cleavage of the terminal alkene vnth osmium tetroxide and sodium periodate (Scheme 5). The indolizidine nucleus was constructed from 39 by a problematic intramolecular aldol condensation, which was eventually optimized by using 2,2,6,6-tetramethylpiperidine as base followed by adsorption onto, and elution from, silica gel (45). Diastereoselective reduction of the ketone group of the aldol product 40 was accomplished in better than 95% enantiomeric excess (ee) with the Corey... 

Introduction. Sodium periodate is widely used for the oxidation of a variety of organic substrates and as a cooxidant in other oxidation reactions (see Sodium Periodate-Osmium Tetroxide and Sodium Periodate-Potassium Permanganate) f The Nal04 oxidation is usually conducted in water however, for organic substrates that are insoluble in water, an organic cosolvent (e.g. MeOH, 95% EtOH, 1,4-dioxane, acetone, MeCN) is used. Alternatively, the oxidation can be conducted either with phase-transfer catalysis (PTC) using quaternary ammonium or phosphonium salts in a two-phase system, or in an organic solvent if the oxidant is first coated on an inert support. ... 

Some additional interesting modifications of this portion of the erythromycin molecule have been reported, although these have not yet apparently led to a useful new antibiotic. Dehydration of the 12-hydroxyl group was reported as a route to the C-12 exomethylene derivative, which was then converted to the corresponding diol with osmium tetroxide and sodium periodate [52]. A ... 

To construct tricycHc compound 275, they first employed sodium boro-hydride to reduce the keto group to furnish alcohol 273. The terminal olefin was then converted to an alcohol via a two-step protocol employing oxidation with osmium tetroxide and sodium periodate followed by reduction with sodium borohydride to furnish diol 274, which underwent acid mediated lactonization. Dess—Martin oxidation of the remaining secondary alcohol then led to the desired tricyclic lactone 275. 

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