Osmium tetroxide primary alcohols

Lead tetraacetate-Manganese(II) acetate, 157 Osmium tetroxide, 222 Potassium ruthenate, 259 Samarium(II) iodide, 270 reagents specific for primary alcohols Osmium tetroxide, 222 reagents specific for benzylic alcohols Cetyltrimethylammonium permanganate, 69... 

Methoxy-2,2,6,6-tetramethyl-1 -oxopiperidinium chloride, 183 Osmium tetroxide, 222 Samarium(II) iodide, 270 Reagents suitable for oxidation of benzyl alcohols but not other primary alcohols... 

Lithium aluminium hydride reduction of 235 followed by mesylation afforded 236. The latter was oxidized with osmium tetroxide and sodium metaperiodate to yield the cyclobutanone 237. Treatment of 237 with acid afforded in 48% yield the ketoacid (238), which was esterified with diazomethane to 239. The latter was converted to the ketal 240 by treatment with ethylene glycol and /7-toluenesulfonic acid. Compound 240 was reduced with lithium aluminium hydride to the alcohol 241. This alcohol had been synthesized previously by Nagata and co-workers (164) by an entirely different route. The azide 242 was prepared in 80% yield by mesylation of 241 and treatment of the product with sodium azide. Lithium aluminium hydride reduction of 242 gave the primary amine, which was converted to the urethane 243 by treatment with ethyl chloroformate. The ketal group of 243 was removed by acidic hydrolysis and the resulting ketone was nitro-sated with N204 and sodium acetate. Decomposition of the nitrosourethane with sodium ethoxide in refluxing ethanol afforded the ketone 244 in 65% yield. The latter had been also synthesized previously by Japanese chemists (165). The ketone 244 was converted to the ketal 246 and the latter to 247... 

Under neutral or acidic conditions osmium tetroxide has been reported to exhibit selectivity fcr the oxidation of primary alcohols, although in the examples shown (equations 14 and IS) the yields appear to be lower than might be desirable (40-30%). ... 

Osmium tetroxide-catalyzed dihydroxylation of the chiral a-acetoxysulfones and acetonide formation affords versatile chemical intermediates. Reduction with DIBAL-H provides primary alcohols, and addition of Grignard reagents provides secondary alcohols with excellent stereochemical control of the newly formed chiral center. ... 

Primary alcohols are oxidized to carboxylic acids by chromium-containing reagents and to aldehydes by PCC or a Swem oxidation. Secondary alcohols are oxidized to ketones. Tollens reagent can oxidize only aldehydes. A peroxyacid oxidizes an aldehyde to a carboxylic acid, a ketone to an ester (in a Baeyer-Villiger oxidation), and an alkene to an epoxide. Alkenes are oxidized to 1,2-diols by potassium permanganate (KMn04) in a cold basic solution or by osmium tetroxide (OSO4). 

The condensation of triphenyl phosphite, benzyl carbamate and 4-pentenal gave the protected a-aminoalkyl phosphonate 313 which was oxidised with osmium tetroxide (Scheme 95). Hydrolysis furnished the diacid 314, which cyclised into phosphonate 315 in the presence of dicyclohexylcarbodiimide. Oxidation of the primary alcohol yielded carboxylic acid 316. Several conventional steps gave the protected oxaphosphane 317 as a separable mixture of stereoisomers. Both cis and trans isomers of 312 have been tested as inhibitors of P-lactamase II from B. cereus and found to be inactive, even at concentrations up to 0.5 mM. 

CH2=C—CH2. The epoxide ring is eventually formed in step H by intramolecular alkylation after the aldehyde group has been reduced to a primary alcohol. Step I is the point at which the stereochemistry of the hydroxyl and methoxy function is established. The osmium tetroxide oxidation insures syn addition. The stereochemistry relative to the alkyl side chain is governed by steric factors. The reagent approaches the double bond from the side opposite the alkyl substituent. The selective methylation of the diol in step J is probably the result of the greater accessibility of an equatorial hydroxyl group. It is the equatorial hydroxyl group that is selectively methylated. The precise selectivity of this step is not entirely clear, since... 

The oxidation of a secondary alcohol to a ketone or a primary alcohol to an aldehyde using dimethyl sulfoxide (DMSO) with oxalyl chloride at low temperature is called the Swern oxidation. Oxidation of an alkene with osmium tetroxide or potassium permanganate gives a cis-l,2-diol. 

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