Kawakami et al.
JOCArticle
of an intermediate activated complex. A positive increase
in the value of ΔSq for the reaction of E10 may result
from activation of alkoxide anions that are being liberated
from the metal ion upon complexation. These experimental
results therefore strongly suggest that the observed dra-
matic rate accelerations of the long oligoether esters with
Ba(OCH2CH3)2 most likely result from the double activa-
tion of the metal complex and its counteranion.
reaction of 1-naphthalene acetic acid and diethyleneglycol
monomethylether: FAB-MS m/z calcd for Mþ (C17H20O4)
288, found 289 (M þ Hþ); 1H NMR (400 MHz, CDCl3,
20 °C) δ 8.01-7.99 (d, 1H, J=8.8 Hz), 7.87-7.85 (d, 1H, J=
7.5 Hz), 7.80-7.78 (q, 1H, J = 3.5 Hz), 7.55-7.47 (m, 2H),
7.45-7.42 (m, 2H), 4.28-4.26 (t, 2H, J=4.8 Hz), 4.11 (s, 2H),
3.66-3.64 (t, 2H, J=4.8 Hz), 3.50-3.48 (m, 2H), 3.45-3.43 (m,
2H), 3.36 (s, 3H); 13C NMR (100 MHz, CDCl3, 20 °C) δ 171.4,
133.7, 132.0, 130.4, 128.6, 127.9, 126.2, 125.6, 125.4, 123.7, 71.7,
70.3, 68.9, 64.0, 58.9, 38.9; IR (KBr) 2879, 1735, 1137, 1109, 782,
cm-1; UV-vis (MeOH, 20 °C) λmax 290, 280, 271 nm. Anal.
Calcd for C17H20O4: C, 70.81; H, 6.99. Found: C, 70.73; H, 6.98.
2-(20(200-Methoxyethoxy)ethoxy)ethyl 1-Naphthaleneacetate
(E5). Compound E5 was isolated as a yellow oil in 22% yield
from the reaction of 1-naphthalene acetic acid and tri-
ethyleneglycol monomethylether: FAB-MS m/z calcd for Mþ
Conclusion
Systematic elongations of the side arm of oligoether esters
E3-E10, which can capture metal ions, in the transesterifi-
cation reactions allowed interesting finding of a novel doubly
activated supramolecular reaction. In comparison with the
shortest E3, which hardly binds the metal ions, oligoether
esters with monovalent metal alkoxides showed selective rate
accelerations due mainly to an effect of host activation, while
dramatic rate enhancement could be achieved in combina-
tions of longer oligoether esters with a divalent metal alk-
oxide as a result of double activation of the host substrate
and guest counter nucleophile at once. Additionally, these
activation effects are accompanied by automatic removal of
the oligoethylene side chain, which provides a notable ad-
vantage, particularly for application in complex synthetic
chemistry sequences. We believe that the supramolecular
reaction presented herein is a general important concept
to control a wide variety of reactions and will ultimately
represent a significant milestone in synthetic chemistry.
1
(C19H24O5) 332, found 333 (M þ Hþ); H NMR (400 MHz,
CDCl3, 20 °C) δ 8.01-7.99 (d, 1H, J=8.8 Hz), 7.87-7.85 (d, 1H,
J=7.5 Hz), 7.80-7.78 (q, 1H, J=3.5 Hz), 7.55-7.47 (m, 2H),
7.45-7.42 (m, 2H), 4.27-4.25 (t, 2H, J=4.8 Hz), 4.11 (s, 2H),
3.66-3.64 (t, 2H, J=4.8 Hz), 3.60-3.58 (m, 2H), 3.54-3.52 (m,
6H), 3.38 (s, 3H); 13C NMR (100 MHz, CDCl3, 20 °C) δ 171.4,
133.7, 132.0, 130.4, 128.6, 127.9, 126.2, 125.6, 125.3, 123.7, 71.8,
70.4, 68.9, 64.0, 58.9, 38.9; IR (KBr) 2879, 1734, 1132, 1108, 784,
cm-1; UV-vis (MeOH, 20 °C) λmax 290, 280, 271 nm. Anal.
Calcd for C19H24O5: C, 68.66; H, 7.28. Found: C, 68.40; H, 7.35.
2-(20-(200-(2000-Methoxyethoxy)ethoxy)ethoxy)ethyl 1-Naph-
thaleneacetate (E6). Compound E6 was isolated as a yellow
oil in 30% yield from the reaction of 1-naphthaleneacetic
acid and tetraethyleneglycol monomethylether: FAB-MS m/z
calcd for Mþ (C21H28O6) 376, found 377 (M þ Hþ); 1H NMR
(400 MHz, CDCl3, 20 °C):δ 8.01-7.99 (d, 1H, J = 8.8 Hz),
7.87-7.85 (d, 1H, J=7.5 Hz), 7.80-7.78 (q, 1H, J=3.5 Hz),
7.55-7.47 (m, 2H), 7.45-7.42 (m, 2H), 4.27-4.25 (t, 2H, J=4.8
Hz), 4.10 (s, 2H), 3.66-3.62 (m, 8H), 3.56-3.54 (m, 6H), 3.37 (s,
3H); 13C NMR (100 MHz, CDCl3, 20 °C) δ 171.4, 133.7, 132.0,
130.4, 128.6, 127.9, 126.2, 125.6, 125.3, 123.7, 71.8, 70.4, 68.9,
Experimental Section
General Procedure for the Synthesis of Oligoether Esters
E3-E10. To a benzene solution (5 mL) of 1-naphthalene acetic
acid 1 (1.8 mmol) was added thionyl chloride (5 mL) and the
reaction mixture refluxed for 2 h and then evaporated to
dryness. The residue was mixed with oligoethyleneglycol mono-
methylether (1.2 mmol) and N,N0-dimethyl-4-aminopyridine
(2.4 mmol) in CH2Cl2 (10 mL) and the solution stirred under
Ar for 24 h at room temperature and then evaporated to dryness.
The residue was then dissolved into ethyl acetate and washed
with aqueous solutions of 1 N HCl, saturated NaHCO3 and
saturated NaCl. The organic layer was then extracted, dried
over anhydrous Na2SO4 and evaporated to dryness. The residue
was subjected to column chromatography on alumina with
CH2Cl2 (for E3-E4) or a mixture of CH2Cl2 and MeOH
(∼10%) (for E5-E10) as eluent, where the second fraction
was collected and evaporated. The products obtained were
unambiguously characterized by means of 1H NMR, 13C
NMR, IR spectroscopy, elemental analysis, and fast atom
bombardment (FAB) mass spectrometry.
64.0, 58.9, 38.9; IR (KBr) 2873, 1734, 1135, 1107, 783, cm-1
;
UV-vis (MeOH, 20 °C) λmax 290, 280, 271 nm. Anal. Calcd for
C21H28O6: C, 67.00; H, 7.50. Found: C, 66.83; H, 7.79.
2-(20-(200-(2000-(20000-Methoxyethoxy)ethoxy)ethoxy)ethoxy)-
ethyl 1-Naphthaleneacetate (E7). Compound E7 was isolated
as a yellow oil in 27% yield from the reaction of 1-naphthalenea-
cetic acid and pentaethyleneglycol monomethylether: FAB-MS
1
m/z calcd for Mþ (C23H32O7) 420, found 421 (M þ Hþ); H
NMR (400 MHz, CDCl3, 20 °C) δ 8.01-7.99 (d, 1H, J=8.8 Hz),
7.87-7.85 (d, 1H, J=7.5 Hz), 7.80-7.78 (q, 1H, J=3.5 Hz),
7.55-7.47 (m, 2H), 7.45-7.42 (m, 2H), 4.27-4.25 (t, 2H, J=4.8
Hz), 4.10 (s, 2H), 3.66-3.62 (m, 12H), 3.56-3.54 (m, 6H), 3.37
(s, 3H); 13C NMR (100 MHz, CDCl3, 20 °C) δ 171.4, 133.7,
132.0, 130.4, 128.6, 127.9, 126.2, 125.7, 125.4, 123.7, 71.8,
70.4, 68.9, 64.1, 58.9, 38.9; IR (KBr) 2873, 1735, 1136, 1109,
784, cm-1; UV-vis (MeOH, 20 °C) λmax 290, 280, 271 nm. Anal.
Calcd for C23H32O7: C, 65.70; H, 7.67. Found: C, 67.28; H, 7.83.
2-(20-(200-(2000-(20000-(200000-Methoxyethoxy)ethoxy)ethoxy)-
ethoxy)ethoxy)ethyl 1-Naphthaleneacetate (E8). Compound E8
was isolated as a yellow oil in 52% yield from the reaction of
1-naphthalene acetic acid and hexaethyleneglycol monomethy-
lether: FAB-MS m/z calcd for Mþ (C25H36O8) 464, found 465
(M þ Hþ); 1H NMR (400 MHz, CDCl3, 20 °C) δ 8.01-7.99 (d,
1H, J=8.8 Hz), 7.87-7.85 (d, 1H, J=7.5 Hz), 7.80-7.78 (q, 1H,
J=3.5 Hz), 7.55-7.47 (m, 2H), 7.45-7.42 (m, 2H), 4.27-4.25 (t,
2H, J=4.8 Hz), 4.11 (s, 2H), 3.66-3.62 (m, 16H), 3.55-3.49 (m,
6H), 3.37 (s, 3H); 13C NMR (100 MHz, CDCl3, 20 °C) δ 171.4,
133.7, 132.0, 130.4, 128.6, 127.9, 126.2, 125.7, 125.4, 123.7, 71.8,
70.4, 68.9, 64.1, 58.9, 38.9; IR (KBr) 2873, 1735, 1136, 1109, 784,
cm-1; UV-vis (MeOH, 20 °C) λmax 290, 280, 271 nm. Anal.
Calcd for C25H36O8: C, 64.64; H, 7.81. Found: C, 64.03; H, 7.76.
2-Methoxyethyl 1-Naphthaleneacetate (E3). Compound E3
was isolated as a yellow oil in 49% yield from the reaction of
1-naphthalene acetic acid and ethyleneglycol monomethylether:
FAB-MS m/z calcd for Mþ (C15H16O3) 244, found 245 (M þ
Hþ); 1H NMR (400 MHz, CDCl3, 20 °C) δ 8.01-7.99 (d, 1H, J=
8.8 Hz), 7.87-7.85 (d, 1H, J=7.5 Hz), 7.80-7.78 (q, 1H, J=3.5
Hz), 7.55-7.47 (m, 2H), 7.45-7.42 (m, 2H), 4.27-4.25 (t, 2H,
J=4.8 Hz), 4.12 (s, 2H), 3.57-3.55 (t, 2H, J=4.8 Hz), 3.32 (s,
3H); 13C NMR (100 MHz, CDCl3, 20 °C) δ 171.5, 133.7, 132.0,
130.4, 128.5, 127.9, 126.2, 125.7, 125.4, 124.0, 70.3, 65.9, 58.8,
38.9; IR (KBr) 2890, 1735, 1171, 1128, 781 cm-1; UV-vis
(MeOH, 20 °C) λmax 290, 280, 271 nm. Anal. Calcd for
C15H16O3: C, 73.75; H, 6.6. Found: C, 73.49; H, 6.85.
2-(20-Methoxyethoxy)ethyl 1-Naphthaleneacetate (E4). Com-
pound E4 was isolated as a yellow oil in 41% yield from the
880 J. Org. Chem. Vol. 76, No. 3, 2011