1,4-dihydronaphthalene naphthalene

As in the case of carbonylation, the reaction of alkynes with nickel metallacycles is often followed by reductive elimination. In some cases, the insertion product is stable and can be isolated (e.g., alkyne insertion in nickelalac-tones or fluorinated metallacycles, Equation (99)), but more frequently it is unstable and decomposes rapidly to afford substituted benzenes, dihydronaphthalenes,naphthalenes, or phenanthrenes. " The reaction of Ni(0) dippe complexes with biphenylene and alkynes in the presence of traces of O2 catalytically produces phenanthrenes, in a process that involves the intermediacy of a carbonickelacycle. " ... 

A number of basic studies in the area of donor solvent liquefaction have been reported (2 -9). Franz (10J reported on the interaction of a subbituminous coal with deuterium-labelled tetra-lin, Cronauer, et al. (11) examined the interaction of deuterium-labelled Tetralin with coal model compounds and Benjamin, et al. (12) examined the pyrolysis of Tetralin-l-13C and the formation of tetralin from naphthalene with and without vitrinite and hydrogen. Other related studies have been conducted on the thermal stability of Tetralin, 1,2-dihydronaphthalene, cis-oecalin and 2-methylin-dene (13,14). 

Another hydrogen atom lost from the a- or 0-Tetralinyl radicals forms either 1,2-dihydronaphthalene by reaction 1 or 1,2- and 1,4-dihydronaphthalene by reactions 2A and 2B. Loss of two more alkyl hydrogens forms naphthalene. The dihydronaphthalenes, which have been detected in low concentrations (6), were not observed under our experimental conditions. 

Now the interesting question arose of whether the intermediate analogous to 215 but devoid of the methyl groups, that is, 3d2-l H-naphthalene (221), would also be interceptable, because 221 should show a high thermodynamic acidity owing to its conversion into the 2-naphthyl anion (224) on deprotonation and because of the use of the strong base KOtBu for the liberation of 221 from 3-bromo-l, 2-dihydro-naphthalene (220) (Scheme 6.52). In the event, the major product was indeed naphthalene. However, there were further products, namely the enol ether 223 and small quantities of 2,2 -binaphthyl (228) as well as 1,2-dihydronaphthalene (226). The overall yield amounted to 92% [137]. 

Scheme 6.52 Generation of 3<52-l H-naphthalene (221) by /j-elimination from 3-bromo-l, 2-dihydronaphthalene (220) and reaction sequences started by attacks of KOtBu at 221.

Wilson and Madsen [152] used the metabolic pathway for bacterial naphthalene oxidation as a guide for selecting l,2-dihydroxy-l,2-dihydronaphthalene as a unique transient intermediary metabolite whose presence in samples from a contaminated field site would indicate active in situ naphthalene biodegradation (Fig. 26). Naphthalene is a component of a variety of pollutant mixtures. It is the major constituent of coal tar [345], the pure compound was commonly used as a moth repellant and insecticide [345], and it is a predominant constituent of the fraction of crude oil used to produce diesel and jet fuels [346]. Prior studies at a coal tar-contaminated field site have focused upon contaminant transport [10,347], the presence of naphthalene catabolic genes [348, 349], and non-metabolite-based in situ contaminant biodegradation [343]. 

Dihalocarbenes, in two-phase catalytic systems, 35 393-398, 408-414 Dihydronaphthalenes, intermediates of naphthalene hydrogenation, 18 32, 33 Diiodocyclodextrin, 32 437-438 Diisopropyl fluorophosphate, as inhibitor, 20 388... 

Under highly protic conditions, the major products of cathodic reductions of cyclic conjugated hydrocarbons are usually dihydro derivatives [56, 57, 187]. In 2-methoxyethanol, for example, naphthalene yields 1,4-dihydronaphthalene [187] and COT mainly provides 1,3,6,-cyclooctatriene [56, 57]. 

Boyd, D.R., McMordie, R.A S., Sharma, N.D., Dalton, H., Williams, P. and Jenkins, R.O., Stereospecific benzylic hydroxylation of bicyclic alkenes by Pseudomonas putida isolation of (+)-/ -l-hydroxy-l,2-dihydronaphthalene, an arene hydrate of naphthalene from metabolism of... 

The specific acid-catalysed solvolysis of l-methoxy-l,4-dihydronaphthalene or 2-methoxy-l,2-dihydronaphthalene has been subjected to kinetic and product studies. The elimination product, naphthalene, predominates. 

Specific acid-catalysed solvolysis of l-methoxy-l,4-dihydronaphthalene or 2-methoxy-l,2-dihydronaphthalene in 25% acetonitrile in water has been found to yield mainly the elimination product, naphthalene, along with a small amount of 2-hydroxy-1,2-dihydronaphthalene, there being no trace of either the 1-hydroxy-1,4-dihydronaphthalene or the rearranged ether. The nucleophilic selectivity, ns/ hoh = 2.1 X 10", between added azide ion and solvent water has been estimated for the relatively stable = 1 x 10 s ) intermediate benzallylic carbocation for which the barrier to dehydronation is unusually low k = 1.6 x 10 ° s ), as evidenced by the large elimination-to-substitution ratio with solvent water as base/nucleophile. The kinetics of acid-catalysed solvolysis of 1-hydroxy-1,4-dihydronaphthalene and 2-hydroxy-1,2-dihydronaphthalene have also been studied. 

In a static-culture-flask screening test, naphthalene (5 and 10 mg/L) was statically incubated in the dark at 25 °C with yeast extract and settled domestic wastewater inoculum. After 7 d, 100% biodegradation with rapid adaptation was observed (Tabak et al, 1981). In freshwater sediments, naphthalene biodegraded to c/5-1,2-dihydroxy-1,2-dihydronaphthalene, 1-naphthol, salicylic acid, and catechol. 

Jerina, D.M., Daly, J.W., Jeffrey, A.M., and Gibson, D.T. cis-l,2-Dihydroxy-l,2-dihydronaphthalene abacterial metabolite from naphthalene, Arch. Biochem. Biophys., 142 394-396, 1971. 

Proton landing defines the basicity of anion-radicals. This landing assumes 1 1 stoichiometry with respect to an anion-radical and a proton donor molecule. For example, in the reaction of the naphthalene anion-radical (CjoH ) with methanol, this 1 1 stoichiometry should result in the formation of 50 50% mixture of naphthalene (CjoHj) and dihydronaphthalene (CioHjo). 

Exposure of naphthalene dissolved in liquid ammonia to europium metal immediately results in the characteristic green color of naphthalene anion-radical. ESR analysis reveals a signal that comes from an unpaired electron interacting with Eu and Eu nuclei. No hyperfine coupling with naphthalene protons is observed, although treatment with water leads to 1,4-dihydronaphthalene (Stevenson et al. 1999). This means that naphthalene has indeed been reduced to its anion-radical and undergone a normal Birch reaction. These results are consistent with the initial donation of two... 

While donor substituents assist in ortho and meta protonation, acceptor substituents direct protonation of the primary anion-radicals to the ipso and para positions. It should be emphasized that water treatment of the naphthalene anion-radical in THF leads to 1,4-dihydronaphthalene. Notably, the same treatment of this anion-radical, but o-bound to rhodium, leads to strikingly different results. In the rhodium-naphthalene compound, an unpaired electron is localized in the naphthalene, but no protonation of the naphthalene part takes places on addition of water. Only evolution of hydrogen was observed (Freeh et al. 2006). Being a-bound to rhodium, naphthalene acts as an electron reservoir. The naphthalene anion-radical part reacts with a proton according to the electron-transfer scheme similar to the anion-radicals of aromatic nitro compounds (see Scheme 1.14). 

Dihydronaphthalen-1,4-iwmes from Isoindoles The naphthalen-l,4-imine derivatives 91-99 have been obtained by addition of acetylenedicarboxylic esters to the appropriate isoindoles. 3- ss Some such adducts react further with acetylenic esters (see Sections III, G and H), so that A -ethyl- and A-n-butylisoindole give 1 2 adducts with dimethyl aoetylenedicarboxylate instead. iV-Methylisoindole appears to be exceptional in giving an oily 2 1 adduct, for which structure (100) was suggested on analogy with the 2 1 adduct obtained from l,3-diphenylbenz[c]furan and acetylenedicarboxylic acid. ... 

Protonic acids and some other electrophiles cause the aromatization of naphthalen-l,4-imines and of derivatives of the related 1,4-epoxy-1,4-dihydronaphthalene ring system (126) to naphthalene derivatives (see Section III,F), and simple electrophilic addition to the 2,3-double bond has not been observed. Ring-opening of the ether (126) also occurs on addition of alkyl or aryl lithium reagents as a result of exo attack by the nucleophile at the 2-position. ... 

When l,4-dihydronaphthalen-l,4-imine (2) was first obtained via the hydrobromide (113), it was shown to react with phenyl azide to give an adduct (127). The analogous phenyl azide adduct (128) from compound 103 has been better characterized. Naphthalen-l,4-imines also add diazomethane across the 2,3-double bond, forming pyrazolines, e.g., 104 -> 129, two of which have been photolyzed to give the corresponding cyclopropane derivatives (130) with extrusion of nitrogen. ... 

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. 

Since different reactivity is observed for both the stoichiometric and the catalytic version of the arene-promoted lithiation, different species should be involved in the electron-transfer process from the metal to the organic substrate. It has been well-established that in the case of the stoichiometric version an arene-radical anion [lithium naph-thalenide (LiCioHg) or lithium di-ferf-butylbiphenylide (LiDTBB) for using naphthalene or 4,4 -di-ferf-butylbiphenyl (DTBB) as arenes, respectively] is responsible for the reduction of the substrate, for instance for the transformation of an alkyl halide into an alkyllithium . For the catalytic process, using naphthalene as the arene, an arene-dianion 2 has been proposed which is formed by overreduction of the corresponding radical-anion 1 (Scheme 1). Actually, the dianionic species 2 has been prepared by a completely different approach, namely by double deprotonation of 1,4-dihydronaphthalene, and its X-ray structure determined as its complex with two molecules of N,N,N N tetramethylethylenediamine (TMEDA). ... 

The methodology was extended to an asymmetric introduction of snbstitnents to a naphthalene ring. When chiral naphthyloxazolines 13 were used as substrates, di- or trisubstituted dihydronaphthalenes 15 were obtained in high diastereomeric ratio (dr) after the treatment of intermediate azaenolate 14 with an electrophile (equation 7) °. Analogous reactions with a chiral naphthaldehyde imine were also reported . 

Oxazoline-directed conjugate addition of nucleophiles to a naphthalene nucleus is one of the most useful methods to prepare dihydronaphthalenes. Since Meyers last comprehensive review, the focus has been directed to stereoselective synthesis of these important compounds. Meyers laboratory has continued their preeminence in this field and has expanded the scope and applications of this reaction. 

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