Lithium aluminum hydride selenium

The preparation of Pans-1,2-cyclohexanediol by oxidation of cyclohexene with peroxyformic acid and subsequent hydrolysis of the diol monoformate has been described, and other methods for the preparation of both cis- and trans-l,2-cyclohexanediols were cited. Subsequently the trans diol has been prepared by oxidation of cyclohexene with various peroxy acids, with hydrogen peroxide and selenium dioxide, and with iodine and silver acetate by the Prevost reaction. Alternative methods for preparing the trans isomer are hydroboration of various enol derivatives of cyclohexanone and reduction of Pans-2-cyclohexen-l-ol epoxide with lithium aluminum hydride. cis-1,2-Cyclohexanediol has been prepared by cis hydroxylation of cyclohexene with various reagents or catalysts derived from osmium tetroxide, by solvolysis of Pans-2-halocyclohexanol esters in a manner similar to the Woodward-Prevost reaction, by reduction of cis-2-cyclohexen-l-ol epoxide with lithium aluminum hydride, and by oxymercuration of 2-cyclohexen-l-ol with mercury(II) trifluoro-acetate in the presence of ehloral and subsequent reduction. ... 

These data indicate a close relationship with ajmalicine, which is supported by chemical evidence. Thus, selenium dehydrogenation gives alstyrine lithium aluminum hydride reduction gives a primary alcohol, akuammigol (I), which possesses a typical indole UV-spectrum, with a deep minimum at 250 m/r. The formulation of this product as an allylic alcohol, stereoisomeric with tetrahydroalstonol, is further shown by its... 

Among the alkaloids of Hunteria ebumea Pichon (Table I) were four interrelated ones (11). Two of them, eburnamine and isoeburnamine, were diastereoisomeric pentacyclic indoles (XVII) convertible by acids into eburnamenine, an A-vinylindole (XVIII), on the one hand, and by chromic acid into eburnamonine, an V-acylindole (XIX), on the other. Reduction of eburnamonine with lithium aluminum hydride regenerated the alcohols, XVII (7,11). When eburnamonine was heated with selenium... 

The reaction of selenium monochloride with propylene was also shown to give the two isomeric bis(/ -chloroalkyl)selenides (86) and (87) via the episelenium intermediate (85) (Scheme 17) <69JOC4003>. As compared to the reaction of propylene with sulfur monochloride, the isomer distribution (86) and (87) remains essentially identical to that observed in the sulfur case within experimental limits. On the other hand, the reaction of 1,5-cyclooctadiene (88) with selenium monochloride was reported to result in the formation of 2,6-dichloro-9-seleno-bicyclo[3.3.1]nonane (89), which can be transformed into the starting cyclooctadiene (88) by treatment with potassium cyanide or lithium aluminum hydride via the episelenium intermediate (90) and episelenide (91) as shown in Scheme 18 <69JOC4003>. 

The conversion of 187 into lycopodine was readily accomplished. Reduction of 187 with lithium aluminum hydride gave the mixture of epimeric alcohols 193 that was oxidized with Jones reagent to the ketone 192. Selenium dioxide gave the known diosphenol 194 which was converted into a separable mixture of lycopodine, anhydro-dihydrolycopodine (195), and dihydrodeoxylycopodine (196) by heating with hydrazine in diethylene glycol at 155°. 

Reaction of that triketone with ethylene glycol selectively forms the expected 3,20-bisacetal the still free remaining ketone at Cn is next reduced with lithium aluminum hydride to yield the expected /8-hydroxyl group (11-1) (Scheme 7.11). Acid hydrolysis of the acetal groups followed by reaction with selenium dioxide generates the... 

ALKENES Allyl dimethyldithiocarbamate. Bis(t -cyclopentadienyl)niobium trihydride. Cyanogen bromide. Di-n-butylcopperlithium. a,o-Dichloromethyl methyl ether. 2,3-Dimethyl-2-butylborane. N,N-Dimethyl dichlorophosphoramide. Diphenyl diselenide. Di-n-propylcopperlithium. Ferric chloride. Grignard reagents. Iodine. Lithium phenylethynolate. Lithium 2,2,6,6-tetramethylpiperidide. Methyl iodide. o-Nitro-phenyl selenocyanate. Propargyl bromide. rra s-l-Propenyllithium. Selenium. Tetrakis(triphenylphosphine)palladium. Titanium(IH) chloride. Titanium trichloride-Lithium aluminum hydride. p-Toluenesulfonylhydrazine. Triphenylphosphine. Vinyl-copper reagents. Vinyllithium. Zinc. 

Amides are converted to iminium salts 98 with oxaly chloride. Selenolysis of 98 with the reagent 99 generated from lithium aluminum hydride and elemental selenium will give selenoamides (Eq. 35) [66]. The reaction is effective... 

A slightly later but obviously independent publication 78) detailed the same structure for dendrobine. A considerable amount of chemical evidence was added to an impressive volume of spectral evidence. Nordendrobine, C15H23O2N (mp 125° [a] — 12.1°), was prepared via the von Braun degradation. It was reconvertible to dendrobine. The isopropyl side chain was recognizable in one of the products of selenium dehydrogenation of dendrobine (but not of dendrobinediol formed by lithium aluminum hydride reduction). The product, 4-isopropyl-2-pyridone, was identical with a synthetic specimen. A still later publication confirmed these findings 79). 

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