Reduction with sodium naphthalene

Treatment with two equivalents of tert-butyl hypochlorite and subsequent reduction with sodium/naphthalene. 

Reduction with sodium naphthalene of easily obtained diazadiene ruthenium ) complexes of type 65 (X = Cl) affords (rj6-arene)Ru(0) complexes 64. The latter are very reactive and undergo oxidative addition with iodine or alkyl halides to produce complexes 65 (X = I and X = CH2R, respectively) (51) [Eq. (26)]. Other ruthenium(O) complexes have been... 

Many reductions with sodium are carried out in boiling alcohols in methanol (b.p. 64°), ethanol (b.p. 78°), butanol (b.p. 117-118°), and isoamyl alcohol (b.p. 132°). More intensive reductions are achieved at higher temperatures. For example reduction of naphthalene with sodium in ethanol gives 1,4-dihydronaphthalene whereas in boiling isoamyl alcohol tetralin is formed. 

Deoxygenation of naphthalene-1,4-endoxides. A new method for conversion of these Diels-Alder adducts of benzynes with furanes to naphthalenes consists in reduction with sodium borohydride in trifluoroacetic acid.5 Excess acid is used when the substrate bears methyl groups at the bridgeheads. Substrates lacking such groups tend to undergo acid-catalyzed rearrangement to naphthols, but are reduced satisfactorily with THF as solvent and a limited amount of acid. 

As discussed above, the absolute stereochemistry of halenaquinone (+)-l and halenaquinol (+)-2 has been theoretically determined by the calculation of the CD spectra of naphthalene-diene derivatives by means of the tt-electron SCF-CI-DV MO method. 18 To apply the same method to these xestoquinone compounds, xesto-quinol dimethyl ether (+)-74 was converted to naphthalene-diene derivative 75 by reduction with sodium borohydride in the presence of cerium(IIl) chloride23 and methanol, followed by treatment with pyridinium p-toluenesulfonate and methanol (Scheme 16).20 The product obtained was a mixture of two stereoisomers of the methoxyl group at the 4-position, from which a single isomer 75 was isolated as... 

Disodium tetracarbonylferrate (Collman s reagent) is prepared by the reduction of Fe(CO)5 with sodium naphthalene in THF or sodium benzophenone ketyl in dioxane. Though it can be isolated as a white precipitate, it is usually used in THF or dioxane solution without isolation because of its highly air-sensitive and pyrophoric character. It is reported that the solubility of Na2[Fe(CO)4] is 7 x 10 M in THF and that it can be stored for moderate periods in an inert atmosphere in the dark [36]. X-ray crystallography of Na2[Fe(CO)4] (Fig. 10.2) shows that the C—Fe—C bond angle opposite to the sodium cations is significantly distorted (129.7°) [37]. However, this distortion is reduced for the potassium analogue [38]. 

We prepared Ni-M (M = Al, Cr, Cu, Co and Mo) catalysts supported on graphite, at low temperature, by coreduction of metal salt mixtures (NiXa, MX2) deposited on this support with sodium naphthalene as reducting agent. Quantitative microanalyses performed by STEM/EDX showed that the two metals were evenly distributed over graphite leaflets. The activity and the selectivity of these catalysts in the hydrogenation of citral to citronellal and citronellol have been compared with that of unsupported bimetallic catalysts, with the same atomic composition and prepared by the same procedure. It appeared that the nickel surface area of the supported catalysts was notably higher than that of the unsupported ones, but the support had almost no effect on the catalytic properties. 

The preeminence of lithium and sodium in metal reductions has been challenged by the use of calcium in amines, developed by Benkeser. In the initial work, naphthalene was reduced to an 80 20 mixture of A -octalin (522) and A ( )-octalin (523) with lithium in diethylamine-dimethylamine. Replacing lithium with calcium gave a 77 23 mixture of 522 and 523 in 92% yield. This method has come to be called the Benkeser reduction. This has become an important modification because Birch reductions with sodium are... 

A number of rate constants of primary alkyl radical reactions have been determined in this way reduction by sodium naphthalenate (2 X 10 sec" ) reaction with lithium benzophenone ketyl radical ... 

The removal of arylsulphonyl groups is often difficult [259]. They are very stable towards alkalis and to bring about acidic hydrolysis usually requires heating with aqueous hydrochloric acid under pressure, or refluxing with 48% hydrobromic acid in the presence of phenol [260, 261]. Arylsulphonamido derivatives are also unaffected by catalytic reduction, however they may be cleaved reductively with sodium in butanol [254] or liquid ammonia [178, 257, 258, 262], or with sodium naphthalene in 1,2-dimethoxyethane [263]. 

Many expensive reductions such as the Birch reduction of naphthalene to isotetralin, benzene to cyclohexene, with metallic sodium and liquid ammonia, or reduction with LiAlHa, can generally be carried out electrochemically at much lower cost and under safe conditions. Electrochemical processes allow fluorinations to be carried out without using fluorine gas. Conducting polymers have been made by electrochemical processes which operate under ambient conditions, and the polymer can be synthesized, doped and shaped in film form in a single step. 

Naphthalene and other aromatic hydrocarbons can be reduced by one electron to produce the anion radical. The reduction can be carried out with sodium in an ether solvent or electrochemically in a polar aprotic solvent. 

Due to the commercial availability of Cp2TiCl2, its reduction and subsequent treatment with CO represents one of the most direct routes to Cp2Ti(CO)2 (1). An early example of this method was reported by Calderazzo et al. whereby Cp2TiCl2 was first reduced by sodium naphthalene at 25°C in THF for 24 hours (16). The resulting green titanocene, p.-(rf i75-fulvalene)-di-/i-hydrido-bis(cyclopentadienyltitanium) (17-22), was then treated with 1 atm of CO in toluene for 4 hours at 20°C. However, this procedure proved inefficient for the production of 1 since only 10% of the required amount of CO for complete conversion was consumed. 

Compounds of this type may only be isolated in the presence of suitable donor molecules, among those, diglyme has been used frequently, but other examples include TMEDA or 2,2,1-crypt for sodium.150 The reduction of naphthalene or anthracene with sodium in diglyme affords separated ions with the radical anion [Na(diglyme)2][naphthalene/anthracene] 139, 140.151... 

H acid (4.2) is possibly the most important single naphthalene-based intermediate. The preparation of this intermediate starts with a high-temperature sulphonation of naphthalene using 65% oleum (anhydrous sulphuric acid in which 65% by mass of sulphur trioxide has been dissolved) to give mainly naphthalene-1,3,6-trisulphonic acid, the nitration product from which is purified by selective isolation. Reduction of the nitro group followed by hydrolysis of the 1-sulphonic acid substituent by heating with sodium hydroxide solution at 180 °C completes the process (Scheme 4.27). 

Naphthylamine and also its sulphonic acids are likewise employed technically for the manufacture of azo-dyes. In the same way a-naph-thol is made from naphthalene-a-sulphonic acid by fusion with sodium hydroxide although on a smaller scale than /3-naphthol. a-Naphthyla-mine, on the other hand, is obtained by the reduction of a-nitronaph-thalene (analogy to aniline). The fusion of alkali salts of arylsulphonic acids with alkali also serves technically for the production of pure phenol and of many phenol derivatives. 

Apart from PET-reductive cyclization, chemical reduction has also been applied to the total synthesis of natural products such as capnellenediol 186 [184]. Naphthalene sodium is shown to be a suitable oxidant for generating ketyl radical anions which cyclize efficiently in a 5-exo-dig mode. In contrast, electroreductive cyclization of 184 does not lead to 185, but exclusively to the thermodynamically preferred 5-exo isomer with a remaining double bond in the endocyclic position [185] (Scheme 35). The steroid precursor 4.5-secocholes-tan-5-one 187, in which the lOa-side chain is varied, has been cyclized under the same conditions [186-188] (Scheme 36). Reduction with naphthalene sodium or sodium in ether exclusively produces the A B-cis steroid 188 with an exo double... 

Reduction of poly(butyl)naphthalenes with sodium-potassium alloy in ether causes their isomerization (Goldberg et al. 1976). The reduction of l,3,6,8-tetra(tcrt-butyl)naphthalene produces an anion-radical, which disproportionates yielding the initial tetrabutylnaphthalene and corresponding dianion (Scheme 6.32). 

The dispersity or homogeneity of the reductant in a reaction system sometimes plays a decisive role. It is also important for synthetic practice. Crandall and Mualla (1986) compared reduction of 7-methylocta-5,6-diene-2-one [H3C-C(CH3)=C=CH-CH2-CH2-C(0)-CH3] in THF by the action of naphthalene-sodium, on the one hand and, by sonically activated sodium on the other. In both the cases, one-electron transfer yields the anion-radical salt of the allenic ketone with sodium. However, only in the case of sonicated sodium is this salt stabilized, eventually giving H3C-C(CH3)=C=CH-CH2-CH2-C(0H)-CH3 along with cyclic products (l-methyl-2-isopropylidene cyclopentanol and l-methyl-2-isopropylcyclopent-2-enol). If naphthalene-sodium is used, only the cyclic alcohols are obtained as mentioned earlier. 

Reduction is defined as acceptance of electrons. Electrons can be supplied by an electrode - cathode - or else by dissolving metals. If a metal goes into solution it forms a cation and gives away electrons. A compound to be reduced, e.g. a ketone, accepts one electron and changes to a radical anion A. Such a radical anion may exist when stabilized by resonance, as in sodium-naphthalene complexes with some ethers [122], In the absence of protons the radical anion may accept another electron and form a dianion B. Such a process is not easy since it requires an encounter of two negative species, an electron and a radical anion, and the two negative sites are close together. It takes place only with compounds which can stabilize the radical anion and the dianion by resonance. 

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