Oxido reaction with

The first step in this preparation, the epoxidation of 1,4,5,8-tetra-hydronaphthalene, exemplifies the well-known selectivity exerted by peracids in their reaction with alkenes possessing double bonds that differ in the degree of alkyl substitution.12 As regards the method of aromatization employed in the conversion of ll-oxatricyclo[4.4.1.01-6]-undeca-3,8-diene to l,6-oxido[10]annulene, the two-step bromination-dehydrobromination sequence is given preference to the one-step DDQ-dehydrogenation, which was advantageously applied in the synthesis of l,6-metliano[10]annulene,2,9 since it affords the product in higher yield and purity. 

Miscellaneous Reactions.- The Schlosser-Wittig reaction of ylide (209) with aldehyde (208) and treatment of the intermediate 6-oxido ylide with perchloryl fluoride has been used to construct the 13-fluoro unit (210) in a total synthesis of (+)-13-fluoroprosta-... 

Dimethyloxetane (296) was opened for the first time by using lithium and a catalytic (20%) amount of DTBB in THF at 0 °C to give the corresponding y-oxido functionalized alkyllithium 297, which by reaction with crotonaldehyde underwent 1,2-addition affording... 

Other chiral oxetanes used to generate chiral y-oxido functionalized organolithium intermediates are 306-309, which gave the expected enantiopure products by reaction with non-prochiral electrophiles"" °. In all cases, when prochiral electrophilic reagents were used, a mixture of the corresponding diastereomers was obtained in variable proportions depending on the electrophile, which could be easily separated by column chromatography. 

Corey and Yamamoto 233) used the P-oxido synthesis 2341 of trisubstituted olefins for the preparation of the acyclic sesquiterpene famesol 433. In this preparation the isoheptenylphosphonium salt 430 is converted into the hydroxyfamesol derivative 432 by reaction with the tetrahydropyranyl ether — protected hydroxy aldehyde 431 and formaldehyde 205. 432 is converted into famesol 433 via several steps. Other reactions of432 likewise proceeding via several steps lead to 434 which is a positional isomer of a C17-juvenile hormone 233) (Scheme 75). 

Chloroperoxidase catalysis by, 58, 302 in chlorination of pyrazoles, 57, 337 Chlorophyll, thioaldehyde synthetic intermediate to, 55, 3 Chlorosulfonyl isocyanate, reaction with 2-arylhydrazono-3-oxobutanoate, 59, 148 Chromatography, of [l,2,4]triazolo[l,5-a]-pyrimidines, 57, 106 Chrom-3-enes, see 2//-l-Benzopyrans Chromium tricarbonyl complexes of 3,5-diphenyl-l-(alkyl- or oxido-)-thiabenzenes, 59, 206, 227 indoles, lithiation of, 56, 181, 184 of pyridine, 58, 160 pyridines, lithiation of, 56, 230, 239 of 2f/-thiopyrans, 59, 227 Chromones, see l-Benzopyran-4-ones Cinnamonitrile, a-cyano-, condensations with thio-, seleno-amides, 59, 184, 186 Cinnoline, nitration, MO calculation, 59, 302... 

Schlosser, M., Christmann, K. F., Piskala, A. Olefinatlon reactions with phosphorus ylides. II. P-Oxido phosphorus ylides in the presence and absence of soluble alkaline metal salts. Chem. Ber. 1970, 103, 2814-2820. 

When the copper-catalysed reactions (type A and type B) were performed in the cavity of an ESR spectrometer, the presence of phenyl radicals was detected by way of their spin adducts with 2-methyl-2-nitrosopropane and with 2,4,6-tribromonitrosobenzene.98 In view of these observations, Dodonov et al. suggested that a free-radical mechanism was involved in both reaction types, A and B, and explained the formation of the hypervalent copper (HI) intermediate. (Scheme 6.23) The copper (HI) intermediate is formed by two consecutive one-electron oxido-reduction elementary steps. The copper (1) catalytic species is first oxidised to a copper(Il) species which is then oxidised by a phenyl rascal to the active copper (HI) intermediate. This hypervalent species then undergoes a ligand coupling reaction with the substrate, either hydroxylic or an amino derivative. In the type B reaction, the in situ generated phenylcopper (III) diacetate reacts with the substrate to eventually afford the O- or the iV-phenyl derivative. 

The efficiency of the arylation is very dependent upon the basicity of the amines. Electron-poor anilines do not react, while electron-rich anilines give high yields of -arylation products. However, in the case of easily oxidised anilines, oxido-reduction of the aryllead reagent can compete with the 7V-arylation when the steric compression becomes too important. For example, in the case of mesitylamine (101), the copper-catalysed reaction with a variety of substituted phenyllead derivatives led to generally high yields of the diarylamines. 

However, in its reaction with the sterically hindered 2,4,6-trimethoxyphenyllead triacetate, the predominant product was the product of oxido-reduction of the aryllead reagent. 

OXIDO de HIERRO (Spanish) (1309-37-1) Violent reactions with powdered aluminum (thermite reaction), hydrogen peroxide, calcium disilicide (thermite reaction), ethylene oxide (may cause explosive polymerization), calcium hypochlorite, hydrazine, hydrogen trisulfide, powdered magnesium. Incompatible with powdered calcium carbide, carbon monoxide, chlorides, guanidinium perchlorate, metal acetylides. Contact with the explosive hydrazinium diperchlorate or ammonium perchlorate can be made more heat-, shock-, or friction-sensitive. Incompatible with aluminum-magnesium-zinc alloys. 

OXIDO de MESITILO (Spanish) (141-79-7) Forms explosive mixture with air (flash point 87°F/31°C). Forms unstable peroxides in storage. Violent reaction with strong oxidizers, 2-aminoethanol, chlorosulfonic acid, 1,2-ethanediamine, ethanolamine, nitric acid, sulfuric acid, oleum. Incompatible with strong acids, aliphatic amines, alkanolamines, ethylene diamine. Dissolves some forms of plastics, resins, and rubber. Attacks copper. 

Schlosser Synthesis of (E)-alkenes. In contrast to the first two examples, this process does not involve equilibration of stereoisomers. The Schlosser method establishes stereochemistry in a kinetically controlled quenching reaction of an oxido ylide with acid. 

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