Sodium periodate-osmium tetroxide

The previously suggested structure (71) for isolongistrobine has been confirmed by synthesis (Scheme 4). TTie amino-alcohol (69) available from related synthetic work (see Vol. 4 of these Reports), was acylated with 4-pentenoyl chloride to give (70), which upon successive oxidation with Cornforth s reagent and oxidative double-bond cleavage with sodium periodate-osmium tetroxide gave isolongistrobine (71)-... 

Related Reagents. Sodium Periodate-Osmium Tetroxide. 

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. ... 

Chemical degradation studies carried out on streptovaricias A and C, which are the primary components of the cmde complex, yielded substances shown ia Figure 1. Streptovaricia A (4), consumes two moles of sodium periodate to yield variciaal A [21913-68-8] (1), 0 2 200, which accounts for the ahphatic portion of the molecule, and prestreptovarone [58074-37-6] (2), C2C)H2C)N02, which accounts for the aromatic chromophore of the streptovaricias (Fig. 2). Streptovaricia G (9) is the only other streptovaricia that yields prestreptovaroae upoa treatmeat with sodium periodate. Treatmeat of streptovaricias A (4), B (5), C (6), E (8), and G (9) with sodium periodate and osmium tetroxide yields streptovarone [36108-44-8] (3), C24H23NO2, which is also produced by the reaction of prestreptovarone with sodium periodate and osmium tetroxide (4,65). A number of aliphatic products were isolated from the oxidation of streptovaricia C and its derivatives (66). 

Osmium tetroxide used in combination with sodium periodate can also effect alkene cleavage.191 Successful oxidative cleavage of double bonds using ruthenium tetroxide and sodium periodate has also been reported.192 In these procedures the osmium or ruthenium can be used in substoichiometric amounts because the periodate reoxidizes the metal to the tetroxide state. Entries 1 to 4 in Scheme 12.18 are examples of these procedures. Entries 5 and 6 show reactions carried out in the course of multistep syntheses. The reaction in Entry 5 followed a 5-exo radical cyclization and served to excise an extraneous carbon. The reaction in Entry 6 followed introduction of the allyl group by enolate alkylation. The aldehyde group in the product was used to introduce an amino group by reductive alkylation (see Section 5.3.1.2). 

In summary, the reaction of osmium tetroxide with alkenes is a reliable and selective transformation. Chiral diamines and cinchona alkakoid are most frequently used as chiral auxiliaries. Complexes derived from osmium tetroxide with diamines do not undergo catalytic turnover, whereas dihydroquinidine and dihydroquinine derivatives have been found to be very effective catalysts for the oxidation of a variety of alkenes. OsC>4 can be used catalytically in the presence of a secondary oxygen donor (e.g., H202, TBHP, A -methylmorpholine-/V-oxide, sodium periodate, 02, sodium hypochlorite, potassium ferricyanide). Furthermore, a remarkable rate enhancement occurs with the addition of a nucleophilic ligand such as pyridine or a tertiary amine. Table 4-11 lists the preferred chiral ligands for the dihydroxylation of a variety of olefins.61 Table 4-12 lists the recommended ligands for each class of olefins. 

If the samples are to be embedded in a resin that is polymerized by UV, such as Lowicryl or LR Gold, do not postfix in osmium tetroxide. Any effect of the osmium on antigenicity can usually be eliminated by using sodium meta-periodate during etching (see step 7). 

Osmium tetroxide used in combination with sodium periodate can also effect alkene cleavage.135 Successful oxidative cleavage of double bonds using ruthenium tetroxide and sodium periodate has also been reported.136 In these procedures, the osmium or ruthenium can be used in substoichiometric amounts because the periodate reoxidizes the metal to the tetroxide state. Entries 1 4 in Scheme 12.17 are examples of these procedures. 

Treatment of 53 with DAST [(diethylamino)sulfur trifluoride] in methylene chloride provided 57 in 50% yield. Compound 57 was treated with osmium tetroxide at 5 °C in the presence of NMO (4-methylmopholine N-oxide) for 18 h to provide 58 and 59, which were separated by silica-gel chromatography. Compounds 58 and 59 were treated with sodium periodate at 5 °C for 18 h to provide 60 and 61 respectively. Compounds 60 and 61 were treated with CDsMgl followed by NaB CN to give 62 in 20% and 50% yields, respectively. 

Exercise 16-37 An elegant modification of the two-step procedure to prepare ketones from alkenes by hydroxylation and oxidative cleavage of the diol formed uses a small amount of potassium permanganate (or osmium tetroxide, 0s04) as the catalyst and sodium periodate as the oxidizing agent ... 

In a first step, the TBS ether is subjected to acid cleavage with copper sulfate in acetone containing a catalytic amount of glacial acetic acid. The resulting diol is then protected as an acetunide. Next, the double bond is oxidatively cleaved with sodium periodate and a catalytic amount of osmium tetroxide to give aldehyde 5. 

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. 

CXXXI. Its properties are those to be expected of such a structure for example, the UV-spectrum shows absorption at 224 m/u. (e = 14000) corresponding to one diene chromophore in the C4o-molecule, and oxidation by osmium tetroxide-sodium chlorate followed by periodate fission gives both acetaldehyde and formaldehyde. The Hofmann degradation can be completed by treatment of descurarine with alkali to yield the ditertiary ether base CXXVIII (129). 

The Step 5 product (410 mg) dissolved in 15 ml THF and 5 ml water was treated with 1.1ml 2.5% solution osmium tetroxide in t-butyl alcohol followed by the portionwise addition of sodium periodate (686 mg), then stirred overnight at ambient temperature. The mixture was concentrated and the residue dissolved in 26 ml... 

The Step 7 product (113 mmol) dissolved in 600 ml dioxane was treated with 200 ml water and 4 ml 4% aqueous solution of osmium tetroxide, then stirred 5 minutes, and treated with sodium periodate (469 mmol). The mixture was heated 3 hours at 35°C, then cooled to ambient temperature, and diluted with 11 EtOAc. The solution was then washed with water, dried, and concentrated. The residue was recrystallized using THF and 15 g of product was isolated. The remaining filtrate was purified by chromatography with silica gel and EtOAc/hexanes, 1 1, so that a total product yield of 44% was observed. 

Sodium periodate, used along with catalytic amounts of osmium tetroxide, radienium dioxide or potassium permanganatt, can also be employed to cleave carbon-carbon double bonds. When used with osmium tetroxide, carbonyls are produced however, the presence of permanganate results in the formation of more highly oxidized products (carboxylic acids) finom secondary carbons. 

Osmium tetroxide reacts with double bonds to form cyclic osmate(VI) diesters (10), which can then be hydrolyzed to provide vicinal diols in good yields. > If, however, sodium perio te is also present, the diol is cleaved, as in Scheme 2, and carbonyl compounds are the final products. Periodate serves the additional purpose of regenerating osmium tetroxide, thus permitting the use of this expensive and toxic reagent in minimum amounts. 

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