Organic Syntheses, CV 6, 862
1,6-OXIDO[10]ANNULENE
Submitted by E. Vogel, W. Klug
1, and A. Breuer.
Checked by D. Knopp, U. Schwieter, and A. Brossi.
1. Procedure
A.
11-Oxatricyclo[4.4.1.01,6]undeca-3,8-diene. A
1-l., three-necked, round-bottomed flask equipped with a
sealed mechanical stirrer, a
pressure-equalizing dropping funnel, and a
thermometer is charged with
66.1 g. (0.501 mole) of 1,4,5,8-tetrahydronaphthalene [
Org. Synth., Coll. Vol. 6, 731 (1988)] and
200 ml. of anhydrous dichloromethane. To the resulting solution is added
75 g. of anhydrous sodium acetate. After the suspension is cooled with an
ice bath,
104.5 g. (0.55 mole) of commercial 40% peracetic acid (Note
1) and (Note
2) is added dropwise over a period of 20–30 minutes, while maintaining the temperature at approximately 15° (Note
3) and stirring vigorously. To the reaction mixture is added, without delay, 500 ml. of water, to dissolve the
sodium acetate and extract the bulk of the
acetic acid. The organic layer is washed successively with two
100-ml. portions of 5% aqueous sodium hydroxide and two 100-ml. portions of water and dried over anhydrous
potassium carbonate. The solvent is removed on a
rotary evaporator, leaving a solid residue. Two recrystallizations from approximately
50 ml. of petroleum ether (b.p.
40–60°), cooling the solution to −40°, yields
58.5–62.0 g. (
79–84%) of
11-oxatricyclo[4.4.1.01,6]undeca-3,8-diene as white needles, m.p.
58–61° (Note
4).
B.
3,4,8,9-Tetrabromo-11-oxatricyclo[4.4.1.01,6]undecane. A 1-l., three-necked, round-bottomed flask fitted with a sealed mechanical stirrer, a pressure-equalizing dropping funnel, and a
calcium chloride drying tube is charged with
59.2 g. (0.400 mole) of 11-oxatricyclo[4.4.1.01,6]undeca-3,8-diene and
500 ml. of anhydrous diethyl ether (Note
5). The resulting solution is cooled in an
acetone–dry ice bath, and
120 g. (0.75 mole) of bromine (Note
6) is added with stirring over a period of 1.5 hours (Note
7). After the addition is complete, the
ether is removed on a rotary evaporator. The solid residue is dissolved in
800 ml. of hot chloroform. To this solution is added, with gentle stirring,
150 ml. of hot petroleum ether (b.p.
60–90°). The resulting, clear mixture, from which the product begins to crystallize, is allowed to cool to room temperature and then stand in a
refrigerator at −40° overnight, completing the crystallization. The yield of white crystalline tetrabromide obtained is
115–125 g. (
61–67%), m.p.
151–153° (Note
8). An additional
18–25 g. of product, m.p.
149–152°, is recovered from the mother liquor by concentration to about one quarter of the volume, giving a total yield of
136–144 g. (
73–77%) of material sufficiently pure to be used in the following step.
C.
1,6-Oxido[10]annulene. A
2-l., three-necked, round-bottomed flask equipped with a sealed mechanical stirrer and a
reflux condenser protected by a calcium chloride drying tube is charged with
81 g. (1.5 moles) of sodium methoxide (Note
9) and
600 ml. of anhydrous ether. To this slurry is added, with stirring,
117 g. (0.250 mole) of finely powdered 3,4,8,9-tetrabromo-11-oxatricyclo[4.4.1.01,6]undecane. The reaction mixture is refluxed with stirring for 10 hours and allowed to stand overnight. Following this, 500 ml. of water is added slowly, dissolving the solids. The
ether layer is separated, and the aqueous layer is extracted with two
100-ml. portions of ether. The combined ethereal solution is washed with 250 ml. of water and dried over anhydrous
potassium carbonate. Removal of the
ether on a rotary evaporator affords a brown oil, which when distilled gives
34.4–35.1 g. of yellow
1,6-oxido[10]annulene, b.p.
77° (0.02 mm.) (Note
10). This material readily solidifies at room temperature, and two recrystallizations at −40° from
225 ml. of (5:1) pentane–ether yields
18.3–18.5 g. (
51%) of
1,6-oxido[10]annulene as pale yellow needles, m.p.
51–52° (Note
11) and (Note
12).
2. Notes
1. Satisfactory
40% peracetic acid is obtainable from Buffalo Electrochemical Corporation, Food Machinery and Chemical Corporation, Buffalo, New York. The specifications given by the manufacturer for its composition are:
peracetic acid,
40%; hydrogen peroxide,
5%; acetic acid,
39%; sulfuric acid, 1%; water, 15%. Its density is 1.15 g./ml. The
peracetic acid concentration should be determined by titration. A method for the analysis of peracid solutions is based on the use of
ceric sulfate as a titrant for the
hydrogen peroxide present, followed by an iodometric determination of the peracid present.
2 The checkers found that
peracetic acid of a lower concentration (27.5%) may also be used without a decrease in yield. The product was found to be sufficiently pure, after only one recrystallization from
60 ml. of petroleum ether (b.p.
40–60°) and cooling overnight to −18°, to be used in the next step.
3. The yields of the desired product decrease substantially if the temperature exceeds 20°.
4. The reported m.p. is
64°.
4 GC analysis using a 1-m. column containing 20% Reoplex 400 on Diatoport S 6080, operated at 160°, indicates the purity of the product to be

98%.
7. The addition of
bromine should not be started before the solution has cooled to approximately −70°.
8. The tetrabromide apparently consists of a mixture of stereoisomers. After several recrystallizations from
chloroform–petroleum ether (60–90°) the major isomer, m.p.
160–162°, is obtained.
9. As reported by Shani and Sondheimer,
3,5 the dehydrohalogenation of the tetrabromide with
potassium hydroxide in
ethanol at 50–55° affords a mixture, readily separated by chromatography on alumina, of
1,6-oxido[10]annulene and the isomeric
1-benzoxepin. The latter compound is also formed during chromatography of
1,6-oxido[10]annulene on silica gel.
6
10. To avoid acid-catalyzed rearrangements of
1,6-oxido[10]annulene it is recommended that the distillation flask be treated with a base before use.
11. The reported m.p. is
52–53°.
6 The purity of the product is greater than 99% as established by TLC, using plates prepared with Silica Gel Si F, obtained from Riedel-De Haen AG, 3016 Seelze, West Germany. If
1,6-oxido[10]annulene is to be used for spectroscopic investigations, care should be taken that its potential contaminants, such as
naphthalene,
1-bromonaphthalene,
α-naphthol, and
1-benzoxepin, are absent, as checked by TLC. The checkers could not obtain the reported yield of
24.5–25.6 g. (
68–71%). Likewise, in experiments where the
ether was replaced with
tetrahydrofuran or
dioxane, the yield given by the submitters could not be obtained.
12. The spectral properties of the product are as follows;
1H NMR (CDCl
3), δ (multiplicity, assignment): 7.25–7.75 (m, AA'BB', aromatic
H); UV (95% C
2H
5OH) nm. max. (ε): 255 (74,000), 299 (6900), 393 (240) complex band; mass spectrum (250°, 70 eV)
m/e (relative intensity > 10%): 144 (M, 43), 116 (40), 115 (100), 89 (15), 63 (15), 51 (10), 39 (11).
3. Discussion
The preparation of
1,6-Oxido[10]Annulene, described simultaneously by Sondheimer and Shani
3,5 and by Vogel, Biskup, Pretzer, and Böll,
6 is illustrative of the rather general synthesis of aromatic 1,6-bridged [10]annulenes from
1,4,5,8-tetrahydronaphthalene. In addition to the present compound, the following bridged [10]annulenes have thus far been obtained by this approach:
1,6-methano[10]annulene,
7,8,9 the 11,11-dihalo-1,6-methano[10]annulenes,
9,10 and 1,6-imino[10]annulene.
11
The epoxidation of
1,4,5,8-tetrahydronaphthalene exemplifies the well-known selectivity of peracids in their reaction with alkenes possessing double bonds that differ in the degree of alkyl substitution.
12 Regarding the method of aromatization employed in the conversion of
11-oxatricyclo[4.4.1.01,6]undeca-3,8-diene to
1,6-oxido[10]annulene, the two-step bromination–dehydrobromination sequence is given preference to the one-step DDQ-dehydrogenation, which was advantageously applied in the synthesis of
1,6-methano[10]annulene,
7,9 since it affords the product in higher yield and purity.
1,6-Oxido[10]annulene closely resembles
1,6-methano[10]annulene in many of its spectral properties, particularly in its
1H NMR, UV, IR, and ESR spectra,
13 but is chemically less versatile than the hydrocarbon analog due to its relatively high sensitivity toward proton and Lewis acids.
This preparation is referenced from:
Appendix
Compounds Referenced (Chemical Abstracts Registry Number)
petroleum ether
1,6-Oxido[10]annulene
ethanol (64-17-5)
potassium carbonate (584-08-7)
sulfuric acid (7664-93-9)
acetic acid (64-19-7)
ether,
diethyl ether (60-29-7)
sodium acetate (127-09-3)
sodium hydroxide (1310-73-2)
chloroform (67-66-3)
bromine (7726-95-6)
α-naphthol (90-15-3)
sodium methoxide (124-41-4)
potassium hydroxide (1310-58-3)
1-bromonaphthalene (90-11-9)
Naphthalene (91-20-3)
hydrogen peroxide (7722-84-1)
Pentane (109-66-0)
dichloromethane (75-09-2)
dioxane (5703-46-8)
Tetrahydrofuran (109-99-9)
peracetic acid (79-21-0)
ceric sulfate (13590-82-4)
1,6-Methano[10]annulene (2443-46-1)
1,4,5,8-Tetrahydronaphthalene (493-04-9)
11-Oxabicyclo[4.4.1]undeca-1,3,5,7,9-pentaene (4759-11-9)
11-Oxatricyclo[4.4.1.01,6]undeca-3,8-diene (16573-72-1)
3,4,8,9-Tetrabromo-11-oxatricyclo[4.4.1.01,6]undecane (16573-82-3)
1-benzoxepin
phosphorus pentoxide (1314-56-3)
m-Chloroperbenzoic acid (937-14-4)
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