2,2a,3,4-Tetrahydro-1H-cyclopent[cd]indene

Rapoport, Henry; Pasky, J. Z.

doi:10.1021/ja01596a061

Cited by 24 publications

(6 citation statements)

References 6 publications

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“…3,4-Dihydro-5-methoxy-15 and 3,4-Dihydro-8-methoxy-l,4epoxynaphthalen-2(1H)-one 16. A solution of the mixture of adducts 1 1 and 12 (920 mg) and PPTS (10 mg) in aq.…”

Section: Figmentioning

confidence: 99%

Regioselectivity in the reactions of methoxydehydrobenzenes with furans. Part 3. 3-Methoxyfuran and methoxydehydrobenzenes and the chemistry of their adducts

Baker¹,

Baker²,

Birkbeck³

et al. 1991

J. Chem. Soc., Perkin Trans. 1

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The cycloadditions of met hoxydehydrobenzenes containing a 3met hoxy group and 3met hoxyfuran are highly regioselective. The adducts, 1,4-dihydro-2-methoxy-1,4-epoxynaphthalenes, undergo mild acid-catalysed hydrolysis providing, first, an isolable 1,2,3,4-tetrahydro-2-methoxy-1,4-epoxynaphthalen-2-01, and then a 3,4-dihydro-l,4-epoxynaphthalen-2(1 H ) -o n e . The chemistry of these ketones is explored. One of them, 3,4-dihydro-5-methoxy-l,4-epoxynaphthalen-2( 1 H ) -one, readily undergoes catalytic reduction t o yield the hexahydro-l,4-epoxynaphthalene-2,5( 1 H,4aH)dione. The X-ray molecular structure of this dione and of the 2-monobrosyl ester of the derived diol are reported. Treatment of the above adducts with trifluoroacetic acid and acetic anhydride provides a convenient synthesis of 1 -acetoxy-2-methoxynaphthalenes.14 could be isolated by fractional crystallization of the crude epoxynaphthalen-2(1H)-one 23 (Scheme 4) (1-H, 6, 5.29 and product. The structural assignment of the hemiacetal 14 is 4-H, 8, 5.88). Therefore the 5-methoxy ketone 15 is that based on its spectral data. The IR spectrum exhibited a band at ketone in which 1-H resonates at 6, 5.01 and 4-H at 6, 5.89. 3370 cm-' attributed to an OH stretching frequency. The ''C and the 8-methoxy ketone 16 is the one in which 1-H resonates NMR spectrum revealed a signal for the methoxy group of the at 6, 5.24 and 4-H at 6, 5.69. in their respective ' H NMR hemiacetal at 6, 50.06, a quaternary carbon atom attributed to spectra. Similar assignments allow distinctions to be made C-2 resonating at 6, 106.39, and the methylene carbon signal between the pairs of ketones 31/32 (Scheme 5), 38/39 (Scheme 6) at 6, 43.02 was attributed to C-3. Nuclear Overhauser effect and 52153 (Scheme 8). (NOE) difference spectroscopy gave evidence for the stereochemistry and the results are shown in Fig. I . Significant interactions are those between the endo-methoxy group at C-2 and both the bridgehead proton 1-H and 3-H,,d,, and between 3-H,,, and the eso-hydroxy group at C-2. Nucleophilic attack by water therefore occurs exclusively from the e.uo-face of the adduct and this mode of attack presumably reflects the unhindered nature of this face of the molecule compared with the endo-face. The spectroscopic properties of the hemiacetal 4 derived from the parent adduct 2 are similar to those of the methoxy derivative 14. In this case the infrared O H stretching 23 9% 19 5% n 39 7% 9 3%* See under section 5.6.

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“…3,4-Dihydro-5-methoxy-15 and 3,4-Dihydro-8-methoxy-l,4epoxynaphthalen-2(1H)-one 16. A solution of the mixture of adducts 1 1 and 12 (920 mg) and PPTS (10 mg) in aq.…”

Section: Figmentioning

confidence: 99%

Regioselectivity in the reactions of methoxydehydrobenzenes with furans. Part 3. 3-Methoxyfuran and methoxydehydrobenzenes and the chemistry of their adducts

Baker¹,

Baker²,

Birkbeck³

et al. 1991

J. Chem. Soc., Perkin Trans. 1

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“…By photolysis of 4-diazo-3,4-dihydro-5(2aH)acenaphthenone (7) [*] in tetrahydrofuran/water (5:l) with a Hg highpressure lamp (Q 81, Quarzlampen-Gesellschaft Hanau) we prepared 2,2a,3,4-tetrahydrocyclopent[cd]indene-l-carboxylic acid (8bjr91 in 36% yield [colorless needles, m. p. The acid (8b) can be dehydrogenated, with simultaneous decarboxylation, in the gas phase by 10% palladized charcoal at 480°C in a high vacuum; the hydrocarbon (4) produced was isolated at -70°C and, after chromatography on Al,O, (activity 3, neutral) at -1O"C, was…”

Section: Synthesis Of 1 H-cyclopent[cd]indene and Its Anion'"]mentioning

confidence: 99%

Synthesis of 1H‐Cyclopent[cd]indene and its Anion

Eilbracht

Häfner

1971

Angew. Chem. Int. Ed. Engl.

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“…16 Replacing the chlorine at C-11 by bromine as in 49 leads to ring closure with formation of 50, which is the all-carbon analog of 46 (Scheme 14) and the chloro derivative of Rapoport and Pasky's hydrocarbon. 23 This reaction probably proceeds by a radical pathway; in support of this interpretation, the same conversion was achieved with NaH-Ni(OAc) 2 , a reagent which reduces aromatic halides via aryl radical intermediates. 24 When both chlorines of 6 are replaced by bromine as in 51, the expected normal bromine-lithium exchange occurs, and it does so even twice with formation of 52; it is of interest that 52 was deuterated to give 53, the 2 H NMR spectrum of which furnished compelling evidence for the intact ring current of its bent benzene system.…”

Section: Reactions With Nucleophilesmentioning

confidence: 80%

“…18c It is suggested that the first step in this transformation is the nucleophilic attack of the tosylamide nitrogen on the ipso carbon C-11 to form 47; in view of the extremely weak basicity of this nitrogen lone pair, the reaction is remarkable indeed. Subsequent hydrolysis of 47 yields 46, which has some interest of its own as being an aniline derivative with a nitrogen lone pair forced into an orientation parallel to the p-system of the benzene ring; incidentally, the ring system of 46 is a nitrogen analogue of a strained hydrocarbon first reported by Rapoport and Pasky 23 (cf. 50 in Scheme 15).…”

Section: Reactions With Nucleophilesmentioning

confidence: 99%

Unusual reactivity of highly strained cyclophanes

Bickelhaupt¹,

Wolf²

1998

J. Phys. Org. Chem.

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An essential feature of the concept of aromaticity has been the stability and lack of reactivity of aromatics relative to that of other unsaturated compounds. Contrary to this general experience, high and unusual reactivity is encountered when simple, monocyclic benzene rings are bent by short bridges into a boat-shaped conformation, as is the case in small [n] paracyclophanes (n 8) and [n]metacyclophanes (n 7). This is illustrated, mostly with examples taken from the authors' own work, for thermal and photochemical behavior and reactions with electrophiles, nucleophiles and dienophiles.

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2,2a,3,4-Tetrahydro-1H-cyclopent[cd]indene

Cited by 24 publications

References 6 publications

Regioselectivity in the reactions of methoxydehydrobenzenes with furans. Part 3. 3-Methoxyfuran and methoxydehydrobenzenes and the chemistry of their adducts

Regioselectivity in the reactions of methoxydehydrobenzenes with furans. Part 3. 3-Methoxyfuran and methoxydehydrobenzenes and the chemistry of their adducts

Synthesis of 1H‐Cyclopent[cd]indene and its Anion

Unusual reactivity of highly strained cyclophanes

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