1.4- Epoxy- 1,4-dihydronaphthalenes

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. ... 

The related oxobicycle (210), on photolysis in carbon tetrachloride, is converted into the isomer (211) in high yield by an intramolecular cycloaddition.186 The same transformation has been observed in norbornadiene, and other intramolecular cycloadditions are known [see, for example, Eq. (50)187]. An intermediate of this type has been postulated188 to account for the photorearrangement of 1,4-epoxy -1,4-dihydronaphthalene to benz[/]oxepin [Eq. (51)]. 

Exhaustive cleavage of the carbon-silicon bond followed by treatment with an acid converted the complex benzo[f]furan 261 to phenol 262, as illustrated in Equation (154) <2003JA12994>. Villeneuve and Tam were able to interrupt this phenol formation by choosing Cp"Ru(COD)Cl as the catalyst. Thus, the reaction of 1,4-epoxy-1,4-dihydronaphthalene 263 with a ruthenium catalyst in 1,2-dichloroethane at 60 °C afforded the 1,2-naphthalene oxide 264 (Equation 155) <2006JA3514>. 

Dihydronaphthalene 1,4-oxide 1,4-Epoxy-1,4-dihydronaphthalene 1,4-Epoxynaphthalene, 1,4-dihydro- (8,9) (573-57-9)... 

The high efficiency of the present precursor 2 is demonstrated by comparison with a similar precursor, 2-(trimethylsilyl)phenyl triflat (4), which generates benzyne under mild conditions (room temperature and neutral).7 Benzyne precursor 2 gives the adduct, 1,4-epoxy-1,4-dihydronaphthalene 3, quantitatively in the reaction with furan, while the reaction of benzyne precursor 4 under the same conditions leads to a lower yield of adduct 3 and needs longer reaction time. 

The reaction of epoxynitriles such as (123) with amines in acetonitrile solution is thought to involve an electron-transfer process. A typical reaction is shown in Scheme 4, whereby irradiation of (123) in acetonitrile with triethylamine affords the amine adduct (124), typical of electron-transfer reactions involving triethylamine with activation of the position a to the amino group. This is accompanied by the isomer (125) of the starting material. The adduct (124) is labile and chromatography on silica gel affords (126). Several examples of this reaction type were published. The direct irradiation of 3-methyl-1,4-epoxy-1,4-dihydronaphthalene-2-carbonitrile brings about its conversion into an indene derivative. ... 

Deoxygenation of 1,4-epoxy-1,4-dihydronaphthalenes. The Diels—Alder adducts of benzynes with furanes can be aromatized by this radical anion in... 

Beside the slow and inefficient initiation, the most important drawback of this first generation Ru-based ROMP and PROMP catalysts was their ionic character, which makes them insoluble in the pure monomers. All polymerizations had to be conducted in solution with polar solvents, which slowed down the reaction even more due to catalyst and monomer dilution. The only monomers which can be photopolymerized in solution or very fast (within seconds) [13] in bulk, are the oxa-benzonorbornenes like 1,4-epoxy-1,4-dihydronaphthalene (M6, R=H, m.p. 55°C) and 4-methyl-l 1-oxa-tricyclo[6.2.1.0 ]undeca-2,4,6,9-tetraene (M7, R=CH3, b.p. 60°C at 0.7 mbar, nD =1.5651) Scheme 3. M6 and M7 are, unfortunately, quite expensive. 

The hydroboration-oxidation studies of 1,4-epoxy-1,4-dihydronaphthalene (1) with various hydroborating agents such as borane-methyl sulfide (BMS), dicy-clohexylborane, disiamylborane, and 9-BBN have yielded interesting results [1]. The reaction of 1 with dicyclohexylborane or disiamylborane affords the exo alcohol 2 without epoxy ring opening (Eq. 32.1). On the other hand, 9-BBN hy-droboration of 1 (1 1 mole ratio) in THE at 25 °C, followed by oxidation affords a homoallylic alcohol 3 after opening of the epoxy ring (Eq. 32.2). BMS, however, affords a mixture of both the alcohols. 

C20H16O2, 1, 4-Epoxy-1,4-dihydronaphthalene photodimer, 35B, 215 C20H16O7, Averufin, 38B, 343... 

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