A R T I C L E S
Hastings et al.
K11[2 ⊂ 1]. 1H NMR (400 MHz, D2O): δ 8.01 (d, 3J ) 7.6 Hz,
for the uncatalyzed and host-catalyzed reactions revealed that
rate enhancements are due to a more positive value of ∆Sq for
the catalytic rearrangement. The catalytic reaction obeys the
Michaelis-Menten model of enzyme kinetics, and competitive
inhibition of this reaction was observed using NPr4+, a
nonreactive guest. These studies demonstrate how supramo-
lecular hosts are able to act as enzyme mimics in the catalysis
of challenging reactions under mild, aqueous conditions. While
a large number of chemical reactions in nature are catalyzed
by enzymes, synthetic chemists have only just begun to realize
the potential of synthetic hosts in catalysis. As new supramo-
lecular hosts are developed and their properties understood, we
anticipate that many new examples of supramolecular catalysis
will be discovered.
3
3
12H, Ar-H), 7.91 (d, J ) 6.8 Hz, 2H, OTs), 7.83 (d, J ) 8.4
3
3
Hz, 12H, Ar-H), 7.69 (d, J ) 8.4 Hz, 2H, OTs), 7.31 (d, J )
3
8.4 Hz, 12H, Ar-H), 7.09 (t, J ) 8.4 Hz, 12H, Ar-H), 6.77 (d,
3J ) 7.2 Hz, 12H, Ar-H), 6.62 (d, J ) 8.0 Hz, 12H, Ar-H),
3
2.37 (s, 3H, OTs), 2.06 (s, 1H, CH, encaps.), 0.52 (s, 1H, CH,
4
encaps.), 0.48 (s, 1H, CH, encaps.), 0.28 (d, J ) 16.0, 1H, CH,
encaps.), -0.06 (s, 3H, CH3, encaps.), -0.14 (s, 3H, CH3, encaps.),
-0.49 (s, 3H, CH3, encaps.), -0.89 (s, 3H, CH3, encaps.). TOF
MS ES(-) m/z calcd (found): Ga4C153H103N13O36K8 [[ - 3K+]3-
1096.0198 (1096.0209); Ga4C153H105N13O36K6 [[ - 5K+]4-
802.53 (802.53).
,
,
K11[3 ⊂ 1]. 1H NMR (400 MHz, D2O): δ 8.04 (s, br, 12H,
Ar-H), 7.82 (d, 3J ) 7.6 Hz, 12H, Ar-H), 7.69, (d, 3J ) 8.0 Hz,
3
3
2H, OTs), 7.35 (d, J ) 8.4 Hz, 2H, OTs), 7.30 (d, J ) 7.6 Hz,
12H, Ar-H), 7.07 (t, 3J ) 7.6 Hz, 12H, Ar-H), 6.76 (d, 3J ) 6.8
3
Hz, 12H, Ar-H), 6.61 (t, J ) 7.6 Hz, 12H, Ar-H), 2.37 (s, 3H,
Experimental Section
OTs), 1.95 (s, 1H, CH, encaps.), 0.65 (s, 3H, CH3, encaps.), 0.57
(d, 1H, CH, encaps.), 0.51 (d, 1H, CH, encaps.), 0.19 (s, 6H, CH3,
encaps.), -0.18 (s, 3H, CH3, encaps.), -1.10 (s, 3H, CH3, encaps.).
TOF MS ES(-) m/z calcd (found): Ga4C154H105N13O36K8 [[ -
General Considerations. Reactions and manipulations were
performed using standard Schlenk and high-vacuum techniques at
room temperature, unless otherwise noted. Glassware was dried in
an oven at 150 °C overnight or flame-dried under vacuum prior to
use. NMR spectra were obtained on Bruker Avance AV 300, AV
400, DRX 500, and AV-500 spectrometers. Chemical shifts (δ)
are reported in parts per million (ppm) relative to residual protonated
solvent resonances. In the case of D2O samples, 13C shifts were
referenced to an internal standard of CD3OD.46 Coupling constants
are reported in Hz. IR spectra were measured neat on a Nicolet
Avatar 370 FT-IR spectrometer with a zinc selenide attenuated total
reflective (ATR) accessory. Peak intensities are reported as broad
(b), weak (w), medium (m), or strong (s). Only peaks in the
functional group region (4000-1300 cm-1) are reported.
Elemental analyses, low-resolution fast atom bombardment
(FAB), high-resolution FAB, and high-resolution electrospray (ES)
time-of-flight (TOF) mass spectrometry (MS) were performed at
the University of California, Berkeley, Microanalytical Facility.
Elemental analyses were performed on a PerkinElmer Series II
CHNO/S analyzer. Reliable combustion analyses for the host-guest
compounds were not possible because of varying amounts of solvent
bound to the exterior of the assembly. FAB mass spectra were
recorded on a Micromass ZAV2-EQ (magnetic sector) instrument.
High-resolution TOF ES-MS of the host-guest complexes were
recorded on a Waters QTOF API mass spectrometer equipped with
a Z-spray source.
Unless otherwise noted, reagents were obtained from commercial
suppliers and used without further purification. Anhydrous solvents
were dried over activated alumina under nitrogen pressure and
sparged with nitrogen before use.47 N,N-Dimethylisobuteny-
lamine,48 4-methyl-2-hexynol,49 and 5-methyl-2-hexynol50 were
prepared according to published procedures.
General Procedure for Encapsulation Reactions. The potas-
sium or sodium salt of 1 (3.0 mg, 0.85 µmol) and the enammonium
tosylate (0.90 µmol) were combined in a vial and dissolved in 600
µL of D2O. The solution was transferred to an NMR tube, and the
spectrum was recorded within 20 min after dissolution. Samples
for mass spectrometry were prepared in an identical fashion, using
H2O instead of D2O. Samples were flushed with N2 after mixing,
and mass spectra were obtained within 12 h of sample preparation.
Analytical Data for Host-Guest Complexes Prepared As
Described Above. In each of the following paragraphs, [ denotes
the host-guest species for which the paragraph gives data.
3K+ 3-
815.776 (815.775).
]
, 1100.692 (1100.693); Ga4C154H106N13O36K7 [[ - 4K+]4-
,
K11[4 ⊂ 1]. 1H NMR (400 MHz, D2O): δ 8.04 (d, 3J ) 7.6 Hz,
12H, Ar-H), 7.76 (d, 3J ) 8.8 Hz, 12H, Ar-H), 7.70 (d, 3J ) 7.7
3
3
Hz, 2H, OTs), 7.38 (d, J ) 8.0 Hz, 2H, OTs), 7.33 (d, J ) 8.0
Hz, 12H, Ar-H), 7.03 (t, 3J ) 8.0 Hz, 12H, Ar-H), 6.78 (d, 3J )
3
6.8 Hz, 12H, Ar-H), 6.62 (t, J ) 8.0 Hz, 12H, Ar-H), 2.40 (s,
2
3H, OTs), 1.76 (s, 1H, CH, encaps.), 0.94 (d, J ) 15.7 Hz, 1H,
CH, encaps.), 0.75 (s, 3H, CH3, encaps.), 0.67 (s, 3H, CH3, encaps.),
0.40 (s, 3H, CH3, encaps.), 0.09 (d, 2J ) 15.4 Hz, 1H, CH, encaps.),
-0.52 (m, 2H, CH2, encaps.), -1.02 (s, 3H, CH3, encaps.), -1.06
(t, 3J ) 7.6 Hz, 3H, CH3, encaps.). TOF MS ES(-) m/z calcd
(found): Ga4C155H107N13O36K8 [[ - 3K+]3-, 1105.364 (1105.364);
Ga4C155H108N13O36K7 [[ - 4K+]4-, 819.280 (819.279).
K11[5 ⊂ 1]. 1H NMR (500 MHz, D2O): δ 8.06 (d, 3J ) 7.5 Hz,
12H, Ar-H), 7.84 (d, 3J ) 9.0 Hz, 12H, Ar-H), 7.64 (d, 3J ) 7.5
3
3
Hz, 2H, OTs), 7.23 (d, J ) 7.5 Hz, 12H, Ar-H), 7.17 (d, J )
3
3
7.5 Hz, 2H, OTs), 7.07 (t, J ) 8.0 Hz, 12H, Ar-H), 6.62 (d, J
3
) 6.5 Hz, 12H, Ar-H), 6.31 (t, J ) 7.5 Hz, 12H, Ar-H), 2.51
(s, 2H, CH2, encaps.), 2.20 (s, 1H, CH, encaps.), 1.34 (s, 2H, CH2,
3
encaps.), 0.50 (q, J ) 12.8 Hz, 2H, CH2, encaps.), 0.10 (s, 3H,
CH3, encaps.), 0.01 (s, 3H, CH3, encaps.), -0.70 (s, 3H, CH3,
encaps.), -0.82 (s, 3H, CH3, encaps.). TOF MS ES(-) m/z calcd
(found): Ga4C156H109N13O36K8 [[ - 3K+]3-, 1110.035 (1110.044);
Ga4C156H110N13O36K7 [[ - 4K+]4-, 822.784 (822.781).
K11[6 ⊂ 1]. 1H NMR (500 MHz, D2O): δ 8.07 (d, 3J ) 6.5 Hz,
3
12H, Ar-H), 7.72-7.67 (m, 14H, Ar-H + OTs), 7.36 (d, J )
3
8.0 Hz, 12H, Ar-H), 7.29 (d, J ) 8.0 Hz, 12H, Ar-H), 7.01 (t,
3
3J ) 8.0 Hz, 12H, Ar-H), 6.74 (d, J ) 7.0 Hz, 12H, Ar-H),
6.59 (t, 3J ) 8.0 Hz, 12H, Ar-H), 1.70 (s, 1H, CH, encaps.), 1.19
(d, 1H, CH, encaps.), 1.10 (s, 3H, CH3, encaps.), 1.03 (s, 1H, CH,
encaps.), 0.73 (s, 3H, CH3, encaps.), -0.36 (d, 1H, CH, encaps.),
-1.03 (s, 3H, CH3, encaps.), -1.48 (s, 3H, CH3, encaps.), -1.60
(s, 3H, CH3, encaps.). TOF MS ES(-) m/z calcd (found):
Ga4C156H109N13O36K8 [[
- , 1110.036 (1110.009);
3K+]3-
Ga4C156H110N13O36K7 [[ - 4K+]4-, 822.784 (822.757).
1
3
Na11[7 ⊂ 1]. H NMR (500 MHz, D2O): δ 8.06 (d, J ) 7.5
3
3
Hz, 12H, Ar-H), 7.75 (d, J ) 8.5 Hz, 12H, Ar-H), 7.70 (d, J
3
3
) 8.5 Hz, 2H, OTs), 7.36 (d, J ) 8.0 Hz, 2H, OTs), 7.33 (d, J
3
) 8.0 Hz, 12H, Ar-H), 6.99 (t, J ) 8.0 Hz, 12H, Ar-H), 6.79
(d, 3J ) 7.0 Hz, 12H, Ar-H), 6.62 (t, J ) 7.5 Hz, 12H, Ar-H),
3
2.01 (s, 1H, CH, encaps.), 1.49 (d, 3J ) 15 Hz, 1H, CH, encaps.),
(46) Gottlieb, H. E.; Kotlyar, V.; Nudelman, A. J. Org. Chem. 1997, 62,
7512–7515.
1.24 (s, 3H, CH3, encaps.), 0.66 (d, 3J ) 35.0 Hz, 6H, (CH3)2,
3
(47) Alaimo, P. J.; Peters, D. W.; Arnold, J.; Bergman, R. G. J. Chem.
Educ. 2001, 78, 64.
encaps.), -0.05 (d, J ) 15.5 Hz, 1H, CH, encaps.), -0.206 (s,
2H, CH2, encaps.), -0.958 (s, 3H, CH3, encaps.), -1.042 (s, 3H,
CH3, encaps.), -1.42 (d, 3J ) 58.5 Hz, 2H, CH2, encaps.), -1.71
(s, 2H, CH2, encaps.). TOF MS ES(-) m/z calcd (found):
Ga4C157H111N13O36Na8 [[ - 3Na+]3-, 1071.7742 (1071.7858);
(48) Ellenberger, M. R.; Dixon, D. A.; Farneth, W. E. J. Am. Chem. Soc.
1981, 103, 5377–5382.
(49) Corey, E. J.; Fuchs, P. L. Tetrahedron Lett. 1972, 13, 3769–3772.
(50) Capon, R. J.; Barrow, R. A. J. Org. Chem. 1998, 63, 75–83.
9
10982 J. AM. CHEM. SOC. VOL. 130, NO. 33, 2008