Unexpected Cleavage of Crown Ether in the Reaction of Methyloxirane with K-,K+(15-crown-5)2

Article abstract of DOI:10.1021/jo981687x

Cleavage of oxirane and crown ether rings occurs when the supramolecular complex K^-,K⁺(15-crown-5)₂ reacts with methyloxirane in tetrahydrofuran solution. Potassium isopropoxide and potassium tetraethylene glycoxide vinyl

Full text of DOI:10.1021/jo981687x

8
990
J . Org. Chem. 1999, 64, 8990-8994
Un exp ected Clea va ge of Cr ow n Eth er in th e Rea ction of
-
+
Meth yloxir a n e w ith K ,K (15-cr ow n -5)
2
Zbigniew Grobelny, Andrzej Stolarzewicz,* and Monika Czaja
Centre of Polymer Chemistry, Polish Academy of Sciences, 41-819 Zabrze, Poland
Wolfgang Demuth and Adalbert Maercker
Institut f u¨ r Organische Chemie, Universit a¨ t Siegen, D-57068 Siegen, Germany
Received August 19, 1998
-
+
Cleavage of oxirane and crown ether rings occurs when the supramolecular complex K ,K (15-
crown-5) reacts with methyloxirane in tetrahydrofuran solution. Potassium isopropoxide and
2
potassium tetraethylene glycoxide vinyl ether are the main products of the reaction. The cleavage
of 15-crown-5 is observed also in the reaction of the metal complex with methyl iodide. That means
that the crown ether acts both as an activator and as a reagent in these processes. The solvent was
inert in the studied systems.
In tr od u ction
Supramolecular complexes of alkali metals containing
complex in tetrahydrofuran solution was selected for the
study because of its particular stability at room temper-
ature.
19
metal anions and cations have previously been known
as the reducing agents of many organic compounds,1-8
as well as the initiators of polymerization of vinyl
Resu lts a n d Discu ssion
monomers,9
-11
dienes,
12,13
lactones
14,15
and oxiranes.
16-18
-
+
2
The K ,K (15-crown-5) solution in tetrahydrofuran
In our earlier work18 on the use of such complexes to
initiate polymerization of methyloxirane, we studied the
mechanism of propagation and chain-transfer reactions.
The rate constants for these reactions were determined.
The initiation was observed to occur instantaneously.
Therefore, it could be neglected when the kinetic equation
which describes the polymerization process was derived.
has a characteristic dark blue color. The signals due to
39
20
both metal ions were present in the K NMR spectrum.
The addition of the supramolecular complex solution into
the solution of methyloxirane caused an instantaneous
discoloration due to the disappearance of potassium
9,21,22
anions.
After that only the signal of potassium cation
was observed in the spectrum. That means that all metal
anions present in the solution took part in the reaction.
To identify the nonvolatile products, methyl iodide was
added after mixing of the reagents. In the chromatogram
of a sample separated from precipitated potassium iodide,
the main product of the reaction was identified as
tetraethylene glycol methyl vinyl ether, i.e., as a methyl
derivative of potassium tetraethylene glycoxide vinyl
ether, in 34% yield. No peak of 15-crown-5 was observed
since the crown ether was displaced as a precipitate in
The present work is a continuation of the study on
polymerization of methyloxirane in the presence of su-
pramolecular metal complexes. Its aim was to explain
-
+
the course of the initiation reaction. K ,K (15-crown-5)
2
(1) Dewald, R. R.; J ones, S. R.; Schwartz, B. S. J . Chem. Soc., Chem.
Commun. 1980, 272.
(2) Mathre, D. J .; Guida, W. C. Tetrahedron Lett. 1980, 21, 4773.
(3) Fish, R. H.; Dupon, J . W. J . Org. Chem. 1988, 53, 5230.
(4) J edli n´ ski, Z.; Kowalczuk, M.; Misiołek, A. J . Chem. Soc., Chem.
Commun. 1988, 1261.
5) J edli n´ ski, Z.; Misiołek A.; Kurcok, P. J . Org. Chem. 1989, 54,
500
6) J edli n´ ski, Z.; Misiołek, A.; J ankowski, A.; J aneczek, H. J . Chem.
Soc., Chem. Commun. 1991, 1513.
7) J edli n´ ski, Z.; Misiołek, A.; J ankowski, A.; J aneczek, H. J .
Organomet. Chem. 1992, 433, 231.
8) Stolarzewicz, A.; Grobelny, Z.; Kowalczuk, M. J . Organomet.
Chem. 1995, 492, 111.
9) Lacoste, J .; Schu e´ , F.; Bywater, S.; Kaempf, B. J . Polym. Sci.,
Polym. Lett. Ed. 1976, 14, 210.
10) J edli n´ ski, Z.; Czech, A.; J aneczek, H.; Kowalczuk, M. J . Am.
Chem. Soc. 1995, 117, 8678.
11) Szwarc, M.; J edli n´ ski, Z.; J aneczek, H. Macromolecules 1997,
0, 4498.
12) Boileau, S.; Kaempf, B.; Raynal, S.; Lacoste, F.; Schu e´ , F. J .
Polym. Sci., Polym. Lett. Ed. 1974, 12, 211.
13) Alev, S.; Collet, A.; Viguier, M.; Schu e´ , F. J . Polym. Sci., Polym.
Lett. Ed. 1980, 18, 1155, 1163.
the form of a complex with potassium iodide.
After solvent evaporation, in the 13C NMR spectrum
(
1
of the sample, aside from the carbon signals of CH
groups in the range of 67-72 ppm, a signal at 59 ppm
arising from the carbons of CH O and the signals due to
the vinyl carbons of the CH dCHsO function at 86.6 and
2
O
(
(
3
(
2
151.7 ppm were found. These observations confirmed the
result of analysis by the GC-MS method.
Further information was provided by the analysis of
samples treated with benzyl bromide instead of methyl
iodide. The signals of two main products of the reaction
were found in the chromatogram. One of them was
(
(
(
3
(
(
(19) Grobelny, Z.; Stolarzewicz, A.; Sok o´ ł, M.; Grobelny, J .; J aneczek
H. J . Phys. Chem. 1992, 96, 5193.
(20) Sok o´ ł, M.; Grobelny, J .; Grobelny, Z.; Stolarzewicz, A. J . Phys.
Chem. 1993, 97, 763.
(
(
(
14) J edli n´ ski, Z. Pure Appl. Chem. 1993, 65, 483.
15) J edli n´ ski, Z.; Lenz, R. W. Macromol. Symp. 1996, 107, 149.
16) Stolarzewicz, A.; Grobelny, Z.; Arkhipovich, G. N.; Kazanskii,
K. S. Makromol. Chem., Rapid Commun. 1989, 10, 131.
17) Buika, G.; Grazulevicius, J . V.; Stolarzewicz, A.; Grobelny, Z.
Macromol. Chem. Phys. 1995, 196, 1287.
18) Stolarzewicz, A.; Grobelny, Z. Makromol. Chem. 1992, 193, 531.
(21) Dye, J . L. In Progress in Macrocyclic Chemistry; Izatt, R. M.,
Christensen, J . J ., Eds.; Wiley-Interscience: New York, 1979; Vol. 1,
pp 63-113.
(
(
(22) Stolarzewicz, A.; Grobelny, Z. Pol. J . Chem. 1986, 60, 577.
1
0.1021/jo981687x CCC: $18.00 © 1999 American Chemical Society
Published on Web 11/17/1999

-
+
Reaction of Methyloxirane with K ,K (15-crown-5)
2
J . Org. Chem., Vol. 64, No. 25, 1999 8991
Sch em e 1
Sch em e 2
identified as benzyl isopropyl ether, i.e., the benzyl
derivative of potassium isopropoxide, in 39% yield. The
other product was found to be tetraethylene glycol benzyl
vinyl ether, i.e., the benzyl derivative of potassium
tetraethylene glycoxide vinyl ether, in 51% yield. The
chromatogram also exhibited a signal due to 15-crown-5
present in the solution after decomplexation of potassium
Sch em e 3
1
3
cations. In the C NMR spectrum of the benzylated
sample, both the signals due to vinyl carbons at 86.6 and
1
3
51.7 ppm, and the signals of CH carbons of the
isopropoxy group at 22.4 ppm were present.
As the potassium isopropoxide was found by benzyl-
ation to be one of the two main products of the examined
reaction, the analysis of the samples subjected to meth-
ylation was repeated. It appeared that the expected peak
of the methyl derivative of potassium isopropoxide, i.e.,
isopropyl methyl ether, could not be observed in the
chromatogram due to its overlapping with the broad peak
The proton exchange in the ion pair 2 results then in
the formation of potassium isopropoxide 3 and potassium
tetraethylene glycoxide vinyl ether 4 after the crown ring
opening (Scheme 2). The proposed course of the reaction
corresponds very well with the similar cleavage of
dimethoxyethane by alkyllithium, yielding methyl vinyl
ether and lithium methoxide.26 Dimethoxyethane may be
treated in this case as a model compound for the
fragment of the crown ether molecule. It is also consistent
with the mechanism for the reactions of organometallic
compounds with simple cyclic ethers, such as 2-alkyl-
substituted tetrahydrofuran or tetrahydropyran, and
nonsubstituted oxepane.27
of the solvent. In turn, the carbon signals of isopropyl
methyl ether could not be recorded in the 13C NMR
spectrum because prior to analysis the volatile ether (bp
3
2 °C) was removed from the methylated sample during
evaporation of tetrahydrofuran.
We assume that the reaction of the supramolecular
potassium complex 1 with methyloxirane starts by the
opening of the oxirane ring in the â position (Scheme 1,
the other 15-crown-5 molecule being omitted). There are
two possible directions of the reaction, i.e., electron
-
transfer or attack of K on the carbon atom from the CH
2
group of the oxirane ring. The mechanism of the reaction
The process described above is very fast. After mixing
of the reagents, potassium anions diminish immediately,
and upon the addition of methyl iodide or benzyl bromide,
the respective methyl and benzyl derivatives of 3 and 4
are obtained (Scheme 3). No products were found in
which methyl or benzyl groups are attached to the carbon
atom associated with potassium in the ion pair 2.
Likewise, no product of the addition of methyloxirane to
that carbon was observed to form. The corresponding
methyl derivatives of byproducts of the reaction were also
identified, i.e., triethylene glycol dimethyl ether and
tetraethylene glycol dimethyl ether, in yields below 10%.
It is worthwhile to note that crown ethers, widely used
in organic syntheses as activators, were until now
considered to be stable. The exceptions were found earlier
only for the self-decomposition of the alkali metal su-
pramolecular complex occurring in tetrahydrofuran solu-
of metal anions with cyclic ethers was studied thoroughly
by J edli n´ ski et al.23 Oxetane was taken as a model
compound in that work. It was found that electron
transfer occurred from potassium anion in that case.
Radical anions were observed in the ESR spectra. This
-
finding was confirmed in the reaction of K with 2-oxe-
tanone.24 Therefore, the electron-transfer mechanism was
accepted in this work for Scheme 1. It is worth emphasiz-
ing that the regioselectivity observed in the reaction of
-
methyloxirane with K is consistent with a mechanism
involving cleavage of the oxirane ring to give the more
substituted alkoxide, rather than the more substituted
radical, as was discussed in ref 25. In that paper the key
references can be found. In particular, the theoretical
explanation for the apparently anomalous direction of
opening is given.
(
23) J edli n´ ski, Z.; Misiołek, A.; J ankowski, A.; J aneczek, H. J .
Organomet. Chem. 1992, 433, 232.
(
24) J edli n´ ski, Z. Pure Appl. Chem. 1993, 65, 483.
(26) Fitt, J . J .; Gschwend, H. W. J . Org. Chem. 1984, 49, 209.
(27) Maercker, A. Angew. Chem., Int. Ed. Eng. 1987, 26, 972, and
references therein.
(25) Dorigo, A. E.; Houk, K. N.; Cohen T. J . J . Am. Chem. Soc. 1989,
1
11, 8976.

8
992 J . Org. Chem., Vol. 64, No. 25, 1999
Grobelny et al.
tion28,29 as well as in the reaction of potassium with
arenocrowns.30 The reactions of metal anions with crown
ethers were slow and led to a mixture of metal glycoxides
and ethylene. The course of the process was described in
Sch em e 4
Sch em e 5
Sch em e 6
-
+
detail for the K ,K (18-crown-6) solution, which decom-
2
8
poses completely after 1.5 h at ambient temperature.
-
+
2
However, the K ,K (15-crown-5) system used in this
work is stable for 1 h after its preparation.19 The
concentration of potassium anions does not change in this
time. Therefore, our finding is the first example that the
crown ether ring is opened when organometallic com-
pound is present in the mixture. Unsaturated alkoxide
is the product of the reaction. Cleavage of the latter by
-
K
affords dipotassium glycoxides, which lead, after
addition of methyl iodide, to the above-mentioned di-
methyl ethers of tetraethylene glycol and triethylene
glycol. It means that the fast reactions observed in this
work and the slow decomposition process of the potas-
sium supramolecular complex have different natures.
Another possible path to dipotassium glycoxides, namely,
by elimination of acetylene from the unsaturated alkoxide
4
, was excluded, since no acetylene was found.
Moreover, it was considered whether the solvent takes
part in the studied processes. It was known that, e.g.,
n-butylpotassium reacts rapidly with tetrahydrofuran
already at -75 °C to afford 2-tetrahydrofurylpotassium,
which decomposed slowly at -75 °C and rapidly at -50
bromide or methyl iodide, no corresponding derivatives
were found.
°
C by fragmentation to ethylene and the potassium
3
1
enolate of acetaldehyde. Tetrahydrofuran, used as the
solvent, was found to be sufficiently acidic to allow rapid
Therefore, the organometallic product of oxirane ring
opening reacts exclusively with crown ether. This process
results in the formation of two metal alkoxides, which
along with the products of side reactions compose a
mixture of the real initiators when the methyloxirane
polymerization is started in the presence of alkali metal
supramolecular complexes.
3
2
protonation of dianions at ambient temperature. It was
1
1
also reported that in the reaction of styrene with
-
+
K ,K (18-crown-6) in tetrahydrofuran there occurs a
partial protonation of styrene dianion by the solvent.
-
+
Therefore, an additional reaction of K ,K (15-crown-5)
2
with methyloxirane in deuterated tetrahydrofuran was
performed. The reaction mixture was treated with benzyl
bromide. After the precipitate was separated and the
It was interesting to determine whether the ring
opening of crown ether occurs exclusively in the presence
-
+
solvent was evaporated, the residue was analyzed by 13
of methyloxirane. Therefore, a reaction of K ,K (15-
crown-5) with methyl iodide was conducted. In this case
C
NMR. No characteristic signals indicating the presence
of deuterium in the structure of the compounds which
could be formed in the reaction of 2 with THF-d were
8
2
organometallic compound was also expected to form as
an intermediate product, as in Scheme 1. A 1:2 mole ratio
of reagents was used, and the products were analyzed
by means of the GC-MS method. The intense peak of
the methyl derivative of unsaturated potassium alkoxide
4 was observed in the chromatogram. The side reactions
afford two glycoxides, as in the case of methyloxirane.
The analysis of gaseous substances demonstrated meth-
ane 8 and ethane 9 to evolve. The liberated gases were
found.
The higher reactivity of crown ether in comparison
with tetrahydrofuran may originate from a specific
activating effect of several oxygen atoms in the polyden-
tate ligand as well as from the fact that crown ether takes
part in the reaction in the form of the complex with
potassium cation.33 The complexation of the cation by the
crown ether molecule would tend to make the C-H bond
more acidic.34
3
determined quantitatively. In an experiment 10 cm of
-
+
0
.1 M K ,K (15-crown-5)
2
solution was added dropwise
The possibility of the reaction of 2 with the CH
3
group
3
to 10 cm of 0.2 M methyl iodide solution in tetrahydro-
of methyloxirane was also taken into account. In such a
reaction potassium allyloxide was assumed to form.35
However, in the reaction mixture treated with benzyl
3
3
furan. In the reaction 8 cm of methane and 14.7 cm of
ethane evolved; i.e., a total of 22.7 cm was found in the
3
liquid and gas phases.
The supramolecular metal complex was concluded
consequently to react with methyl iodide as shown in
Scheme 4. Then, the crown ether molecule undergoes ring
opening, leading to the formation of potassium tetra-
ethylene glycoxide vinyl ether 4. Liberation of methane
occurs simultaneously (Scheme 5). It is accompanied by
the formation of ethane (Scheme 6). According to Schemes
(
28) J edli n´ ski, Z.; Stolarzewicz, A.; Grobelny, Z. Makromol. Chem.
986, 187, 795.
29) Cauliez, P. M.; J ackson, J . E.; Dye, J . L. Tetrahedron Lett. 1991,
2, 5039.
30) Sok o´ ł, M.; Kowalczuk, M.; Grobelny, Z.; J aneczek, H.; J edli n´ ski,
Z.; Luboch, E.; Biernat, J . J . Org. Chem. 1995, 60, 2365.
1
(
3
(
(
(
31) Lehmann, R.; Schlosser, M. Tetrahedron Lett. 1984, 25, 745.
32) Levin, G.; J agur-Grodzinski, J .; Szwarc, M. J . Am. Chem. Soc.
1
970, 92, 2268.
(
(
(
33) Dye, J . L. J . Phys. IV 1991, 1, C5-259.
34) Dye, J . L. Pure Appl. Chem. 1989, 61, 1560.
35) Stolarzewicz, A. Makromol. Chem. 1986, 187, 745 and refer-
4
-6 the theoretically calculated total volume of methane
3
and ethane was 22.4 cm . It was found to be in good
ences therein.
agreement with the experimental results.

-
+
Reaction of Methyloxirane with K ,K (15-crown-5)
2
J . Org. Chem., Vol. 64, No. 25, 1999 8993
Con clu sion s
Oxirane and crown ether rings are cleaved in the
-
+
2
reaction of methyloxirane with K ,K (15-crown-5) su-
pramolecular complex in tetrahydrofuran solution. Metal
alkoxides are the products of the reaction. The process
is accompanied by side reactions, but no products of
solvent decomposition were found. It was also shown that
the crown ether ring opening reaction is not confined to
the system containing methyloxirane.
Crown ethers, widely used in organic synthesis as
activators, are considered, with some exceptions,2
8-30
to
F igu r e 1. Apparatus for the preparation of the solution of
the metal supramolecular complex and for its reaction with
methyloxirane or with methyl iodide: (A) test tube; (B) reactor
for preparing the metal solution; (C) calibrated test tube; (D)
glass frit; (E) reactor for conducting the process.
be stable. The reactions reported here demonstrate the
possibility of their decomposition also in processes involv-
ing organometallic compounds.
Exp er im en ta l Section
after the addition of methyl iodide was found to be present in
the precipitate along with potassium iodide. When benzyl
bromide was used, potassium cation underwent decomplex-
ation and crown ether remained in the solution. Other reac-
tions were conducted in the same way.
An a lytica l Meth od s. GC-MS analyses were run on a 30
m long DB 1701 fused silica capillary column, using a Varian
300 gas chromatograph equipped with a Finnigan MAT 800
AT ion trap detector. The methylated or benzylated products
were identified by comparing their mass spectra and retention
times with those of authentic compounds. Diethylene glycol
dimethyl ether was used as the internal standard for the yield
measurement.
3
Ben zyl Isop r op yl Eth er (5). The method of its synthesis
as well as its NMR and mass spectral data are given in refs
3
6-39, respectively.
Tetr a eth ylen e Glycol Meth yl Vin yl Eth er (6). A 0.10 g
3
(
2.5 mmol) sample of potassium hydride and 10 cm of
Gaseous products were identified by GC with a 2.4 m long
tetrahydrofuran were introduced into the reactor. Then, 0.33
g (2.5 mmol) of diethylene glycol vinyl ether was added
dropwise. The course of the reaction was monitored by
measuring the amount of hydrogen liberated. After 7 h of
stirring, 0.46 g (2.5 mmol) of 1-bromo-2-(2-methoxyethoxy)-
ethane was added dropwise into the solution. After another 2
h of stirring, the potassium bromide precipitate was separated
by decantation. The product present in the solution was
distilled in a Kugelrohr apparatus; the fraction boiling at 100
stainless steel column packed with Al
tivated with 5% K CO , in an INCO 505 gas chromatograph
equipped with a flame ionization detector.
2 3
O , 0.2-0.3 mm, deac-
2
3
1
13
39
H, C, and K NMR spectra were recorded at 20 °C on a
Varian VXR-300 multinuclear pulsed spectrometer operating
1
13
at the H resonance frequency of 300 MHz, the C resonance
3
9
frequency of 75 MHz, and the K resonance frequency of 14
MHz. Chemical shifts were referenced to tetramethylsilane
1
13
serving as an internal standard for H and C measurements.
To obtain a satisfactory signal-to-noise ratio, about 30 000
°
C, 0.15 mbar, consisted of tetraethylene glycol methyl vinyl
1
ether. H NMR (acetone-d
6
): δ 6.50 (dd, J ) 14.4, 6.8 Hz, 1H,
d); 4.01 (dd, J )
d); 3.52-3.88 (m, 16H, OCH ); 3.38 (s,
). C NMR (acetone-d ): δ 151.7 (OCHd); 86.5
d); 67.1-71.9 (OCH , 6 signals); 58.9 (CH ). MS: m/e (rel
intens) 189 (M - 45, 0.1); 175 (0.5); 159 (1); 133 (3); 117 (4);
03 (15), 87 (18), 73 (21), 59 (100), 45 (96), 43 (46); 29 (33).
Tet r a et h ylen e Glycol Mon ob en zyl E t h er (H O[CH
CH O] CH P h ). An 80% dispersion of NaH (7.8 g containing
.26 mol of NaH) in paraffin was washed twice with tert-butyl
1
3
scans were accumulated for C spectra. Deuterated acetone
OCHd); 4.18 (dd, J ) 14.4, 2.2 Hz, 1H, CH
2
was used to dissolve the organic compounds, and D
inorganic compounds.
Ma ter ia ls. Methyloxirane (Aldrich) was heated over CaH
for 6 h, and then distilled under a dry argon atmosphere; the
fraction boiling at 35 °C was collected. Tetrahydrofuran
POCH) was boiled over CuCl to decompose peroxides and then
2
O for
6
3
.8, 2.2 Hz, 1H, CH
2
2
13
H, OCH
3
6
2
(CH
2
2
3
1
(
2
-
over CaH for 10 h, and finally it was distilled at 66 °C. This
2
2
4
2
fraction was dried over metallic potassium for 20 h and
redistilled prior to use. 15-Crown-5 (Aldrich) was dried under
vacuum at 50 °C for 8 h. Potassium (Fluka) was purified in
boiling tetrahydrofuran. Potassium hydride (Aldrich) was
purified from paraffin oil by repeated extraction with hexane.
Triethylene glycol dimethyl ether and tetraethylene glycol
dimethyl ether (both Aldrich) were used as model compounds.
Gen er a l P r oced u r e. Preparation of the solution of the
supramolecular metal complex and its reaction with methyl-
oxirane were accomplished in an apparatus equipped with
Teflon valves enabling substrate delivery and sampling under
an argon atmosphere (Figure 1). About 2 g of potassium was
placed in a test tube (A) and degassed and distilled under high
0
methyl ether and decanted; the NaH was suspended in 100
mL of tetrahydrofuran, and then a mixture of tetraethylene
glycol (48.5 g, 0.25 mol) and 50 mL of tetrahydrofuran was
added dropwise. After the evolution of hydrogen had stopped,
benzyl bromide (25.6 g, 0.15 mol) was added and the reaction
mixture stirred for 2 h. Water was added, the organic layer
separated, and the aqueous phase extracted with tert-butyl
methyl ether. The combined organic phases were dried and
the solvents removed under reduced pressure. The crude
product (37 g) was used in the next step without further
purification.
Tetr a eth ylen e glycol ben zyl vin yl eth er (7) was pre-
-
5
vacuum (ca. 10 bar) into the reactor (B). The distillate was
again molten and heated under vacuum to remove the residual
amounts of volatile impurities, giving rise to a metal layer at
the bottom of the reactor.
40
pared by the transetherification method. A stirred solution
of crude tetraethylene glycol monobenzyl ether (37 g, 0.13 mol),
butyl vinyl ether (60 g, 0.60 mol), and mercury trifluoroacetate
(1.2 g, 2.8 mmol) was heated for 1 h under reflux, then
-
+
2
The 0.1 M solution of K ,K (15-crown-5) was obtained by
anhydrous potassium carbonate (2 g, 20 mmol) was added, and
3
ultrasonic dissolution of potassium in 10 cm of 0.2 M 15-
crown-5 solution in tetrahydrofuran, as in ref 19. The metal-
(
36) Eichinger, P. C. H.; Bowie, J . H.; Blumenthal, T. J . Org. Chem.
c
solvent contact time, t , was 25 min. The obtained solution was
1
986, 51, 5078.
filtered into a calibrated test tube (C).
(37) Ochiai, M.; Ito, T.; Takahushi, H.; Nakanishi, A.; Toyonari, M.
The reaction was performed at 25 °C in a 50 cm3 reactor
J . Am. Chem. Soc. 1996, 118, 7716.
38) Barluenga, J .; Alonso-Cires, L.; Campos, P. J .; Asensio, G.
Synthesis 1983, 1, 53.
39) Ortiz, B.; Walls, F.; Yuste, F.; Barrios, H.; Sanchez-Obregon,
(
(
E) equipped with a magnetic stirrer and filled with dry argon.
3
A 10 cm sample of freshly prepared supramolecular complex
solution was added to 10 cm of 1.0 M methyloxirane solution
(
3
R.; Pinelo, L. Synth. Commun. 1993, 23, 749.
(40) Watanabe, W. H.; Comlon, L. E. J . Am. Chem. Soc. 1957, 79,
2828.
in tetrahydrofuran. Then methyl iodide or benzyl bromide was
introduced immediately to the reaction mixture. 15-Crown-5

8
994 J . Org. Chem., Vol. 64, No. 25, 1999
Grobelny et al.
+
the excess of butyl vinyl ether was removed under reduced
pressure. A sample of the residue was distilled in a Kugelrohr
apparatus; the fraction boiling at 145 °C, 0.05 mbar, consisted
signals); 58.8 (OCH
3
). MS: m/e (rel intens) 179 (M , 2), 133
(22), 103 (59), 89 (36), 73 (8), 58 (100), 45 (86), 43 (44).
Tetr a eth ylen e Glycol Dim eth yl Eth er (CH O[CH
): δ 3.44-3.59 (m, 16H,
). C NMR (acetone-d ): δ 72.6-
, 4 signals); 58.8 (OCH ). MS: m/e (rel intens) 223
3
2
-
1
1
of tetraethylene glycol benzyl vinyl ether in 66% yield. H NMR
CH
OCH
71.0 (OCH
2
O]
2
4 3 6
CH ). H NMR (acetone-d
1
3
(
1
1
acetone-d
6
): δ 7.34 (m, 5H, C
H, OCHd); 4.56 (s, 2H, PhsCH
H, CH d); 3.97 (dd, J ) 6.8, 2.2 Hz, 1H, CH
6
H
5
); 6.50 (dd, J ) 14.4, 6.8 Hz,
); 4.23 (dd, J ) 14.4, 2.2 Hz,
d); 3.63-3.86
): δ 151.7 (OCHd);
); 86.5 (dCH ); 73.2 (PhsCH );
, 6 signals). MS: m/e (rel intens) 310 (M ,
), 223 (1); 177 (5), 133 (15); 105 (17), 91 (100), 73 (19); 45
); 3.28 (s, 6H, OCH
3
6
2
2
3
+
2
2
(M , 1), 177 (2), 133 (6), 103 (31), 87 (14), 59 (100), 45 (8), 43
(44).
1
3
(m, 16H, OCH
2
). C NMR (acetone-d
38.2, 128.3, 127.7, 127.5 (C
7.1-70.7 (OCH
6
1
6
2
6
H
5
2
2
+
2
Ack n ow led gm en t. We are indebted to Dr. Gra z˘ yna
Adamus for performing the chromatographic analyses,
and to Dr. J anusz Grobelny for conducting the NMR
measurements.
(62), 43 (30).
Tr ieth ylen e Glycol Dim eth yl Eth er (CH
3
O[CH
2
CH
); 3.28
): δ 72.6-71.0 (OCH , 3
2 3
O] -
1
CH
3
). H NMR (acetone-d
6
): δ 3.44-3.58 (m, 12H, OCH
2
1
3
(
s, 6H, OCH
3
). C NMR (acetone-d
6
2
J O981687X