Naphthalene reduction

Methoxytetralin, substituted naphthalene reduction to tetralin, 132-133 Methyl-2-(phenylcarbamoyl)butanoate, a,-unsaturated ester hydrocarbamoylation, 134 4-Methylbenzyl chloride [reductive... 

Under nominally aprotic conditions, 1,2-protonation dominates in naphthalene. Reduction of naphthalene in anhydrous acetonitrile containing tetraethylammo-nium p-toluenesulfonate yields 1,2-di-hydronaphthalene, which is subsequently... 

Sodium-naphthalene reduction of organotrineopentoxyphosphonium salts led to the instantaneous loss of phosphonium ion phosphonates and phosphites were obtained748 (reaction 224). Alkali metal amalgams are efficient reagents for the reductive cleavage of both achiral and optically active phosphonium salts configuration is retained750 (Table 23). 

By oxidising the sulfide to a sulfone, the synthetic versatility of this class of compounds is further increased. Deprotonation of either or both diastereoisomers of 98 leads, under thermodynamic control, to the equatorial organolithium 101 in which a destabilising interaction between the oxygen lone pair and the lithio substituent is avoided. However, lithium-naphthalene reduction of 102 to the organolithium 103 is axially selective because of the stabilisation afforded to the intermediate radical by the axial lone pair. Protonation of the product gives 104.88... 

Radical cations have also been trapped with the hydride ion. Irradiation of aromatic hydrocarbons such as phenanthrene, anthracene and naphthalene in aqueous acetonitrile containing sodium borohydride and an electron acceptor produces the dihydroarenes (Yasuda et ai, 1981b). With monoalkyl naphthalenes reduction in both the unsubstituted and substituted rings occurs... 

Under nominally aprotic conditions, 1,2-protonation dominates in naphthalene. Reduction of naphthalene in anhydrous acetonitrile containing tetraethyl ammonium p-toluenesulfonate yields 1,2-dihydronaphthalene, which is subsequently reduced to tetralin [169]. Similarly, reduction of I in anhydrous DMF gives 1,3,5-cyclooctatriene almost exclusively [53]. The formation of the thermodynamically more stable products is most probably due to base-catalyzed isomerization. 

In order to reduce the crystallinity of the polyketal an unsymmetrical cyclic diketone was prepared from 2,7-dihydroxy-naphthalene. Reduction of the naphthalene nucleus with Raney nickel and hydrogen gave a 90% yield of the 2,7-decalindiol, which on oxidation with chromic acid gave a 50% yield of the 2,7-deca-lindione. When this diketone was condensed with the tetrakis-(hydroxymethyl) cyclohexane, an 89% yield of a white polymer VIII was obtained which did not melt and was soluble only in hexa-fluo ro isopropano1. 

The lithium-naphthalene reduction has been successfully extended to other metals. Platinum metal so prepared reacts at room temperature with allyl iodide. Cobalt metal reacts with allyl bromide to yield 1,5-hexadiene without any evidence of an organocobalt compound. Iron powder reacts very vigorously with allyl bromide at room temperature to yield 1,5-hexadiene. 

In contrast, for reaction of organic halides with metallic magnesium, Whitesides ( 7) found a poor correlation with the rates of tri-n-butyltin hydride, and a reasonable correlation, especially with primary bromides, with reduction potentials, suggesting the formation of RXT. Sodium naphthalene reductions also correlate with reduction potentials for primary halides (4b). Moreover, reaction rates are faster in solvents favoring loose ion pairs over tight, further evidence for an early transition state involving election transfer and little bond dissociation. (4c)... 

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