A R T I C L E S
Gu et al.
of Al-F and decrease in the intensity of the 19F NMR resonance
of F substrates (δ -65.3 (p-FC6H4CF3), -110.1 (p-FC6H4CF3)).
Yield (based on 19F NMR, after 24 h): FC6H4CH2CH2CH3, 8%;
FC6H4CHEt2, 28%; FC6H4CEt3, 6%.
Entry 15. A 40 µL (300 µmol) volume of substrate 3 was mixed
with 125 µL (914 µmol) of triethylaluminum, 5.0 µL (43 µmol) of
C6F6, and 62 µL of Et2Al[HCB11H5Br6] solution (predissolved in
o-dichlorobenzene, 1 mg/30 µL, 3 µmol) in a J. Young tube. A
colorless solution was formed. The mixtures were allowed to stay
at room temperature for 24 h. The reactions were monitored by
detecting the increase in the intensity of the 19F NMR resonance
of Al-F and decrease in the intensity of the 19F NMR resonance
of F substrates (δ -66.0 (ClC6H4CF3)). The ratio of products in
GC/MS is 13:68:19 ClC6H4CH2CH2CH3:ClC6H4CHEt2:ClC6H4CEt3.
Entry 16. Five solutions containing C6H5CMe3 and C6H5Br in
different ratios were prepared and analyzed by GC/MS. Integration
of the corresponding peaks in the resulting chromatogram gave the
coefficient as 1.029 (see the details in the SI). The reaction (entry
17) was set up using 40 µL (326 µmol) of substrate 2 with 2.3 mg
(3.3 µmol) of Et2Al[HCB11H5Br6], 5.0 µL (43 µmol) of C6F6, and
490 µL of AlMe3 (980 µmol, 2 M in hexanes) in 0.5 mL of hexanes.
After 36 h, 19F NMR indicated that 94% of C-F was converted. A
60 µL (572 µmol) volume of bromobenzene was added to the
reaction mixture, and the mixture was filtered through Celite, diluted
by hexanes, and analyzed by GC/MS. Integration of the resulting
chromatogram gave a ratio of 0.48:1.00 corresponding to the
formation of 283 (0.48 × 1.029 × 572) µmol of C6H5CMe3. Yield:
87%.
Entry 17. A 40 µL (280 µmol) volume of substrate 4 was mixed
with 115 µL (840 µmol) of AlEt3, 5.0 µL (43 µmol) of C6F6, and
11.8 mg (16.8 µmol) of Et2Al[HCB11H5Br6] in a J. Young tube. A
clear solution was formed. The mixture was heated at 85 °C for
24 h. The reactions were monitored by detecting the increase in
the intensity of the 19F NMR resonance of Al-F and decrease in
the intensity of the 19F NMR resonance of F substrates (δ -58.9
(C6F5CCF3),-142.4(C6F5CCF3),-149.8(C6F5CCF3),-162.4(C6F5-
CCF3)). The ratio of products in GC/MS is 31:61:8 C6F5CH2CH2-
CH3:C6F5CHEt2:C6F5CEt3.
Entry 18. A 40 µL (280 µmol) volume of substrate 4 was mixed
with 420 µL (840 µmol) of AlMe3 (2 M in hexanes), 5.0 µL (43
µmol) of C6F6, and 360 µL (16.8 µmol) of Et2Al[HCB11H5Br6]
solution (1 mg/30 µL of o-dichlorobenzene) in a J. Young tube. A
clear solution was formed. The mixture was heated at 85 °C for
24 h. The reactions were monitored by detecting the increase in
the intensity of the 19F NMR resonance of Al-F and decrease in
the intensity of the 19F NMR resonance of F substrates (δ -58.9
(C6F5CCF3), -142.4 (C6F5CCF3), -149.8 (C6F5CCF3), -162.4
(C6F5CCF3)). Yield (based on 19F NMR, after 24 h): C6F5CMe3,
84%.
Entry 19. A 40 µL (280 µmol) volume of substrate 4 was mixed
with 420 µL (840 µmol) of AlMe3 (2 M in hexanes), 5.0 µL (43
µmol) of C6F6, and 60 µL (2.8 µmol) of Et2Al[HCB11H5Br6] solution
(1 mg/30 µL of o-dichlorobenzene) in a J. Young tube. A clear
solution was formed. The mixture was heated at 85 °C for 24 h.
The reactions were monitored by detecting the increase in the
intensity of the 19F NMR resonance of Al-F and decrease in the
intensity of the 19F NMR resonance of F substrates (δ -58.9
(C6F5CCF3), -142.4 (C6F5CCF3), -149.8 (C6F5CCF3), -162.4
(C6F5CCF3)). Yield (based on 19F NMR, after 24 h): C6F5CMe3,
38%.
Entry 9. A 40 µL (315 µmol) volume of substrate 1 was mixed
with 130 µL (950 µmol) of triethylaluminum, 5.0 µL (43 µmol) of
C6F6, and 2.7 mg (3.2 µmol) of Ph3C[HCB11H5Br6] in a J. Young
tube. A colorless solution was formed. A dramatic elevation of
temperature was observed at the beginning of the reaction. The
mixtures were allowed to stay at room temperature for 24 h. The
reactions were monitored by detecting the increase in the intensity
of the 19F NMR resonance of Al-F and decrease in the intensity
of the 19F NMR resonance of F substrates (δ -65.3 (p-FC6H4CF3),
-110.1 (p-FC6H4CF3)). Yield (based on 19F NMR, after 24 h):
FC6H4CH2CH2CH3, 8%; FC6H4CHEt2, 51%; FC6H4CEt3, 32%.
Entry 10. A 40 µL (315 µmol) volume of substrate 1 was mixed
with 130 µL (950 µmol) of triethylaluminum, 5.0 µL (43 µmol) of
C6F6, and 2.9 mg (3.2 µmol) of Ph3C[B(C6F5)4] in a J. Young tube.
A colorless solution was formed. The mixtures were allowed to
stay at room temperature for 24 h. The reactions were monitored
by detecting the increase in the intensity of the 19F NMR resonance
of Al-F and decrease in the intensity of the 19F NMR resonance
of F substrates (δ -65.3 (p-FC6H4CF3), -110.1 (p-FC6H4CF3)).
Yield (based on 19F NMR, after 24 h): FC6H4CH2CH2CH3, 8%;
FC6H4CHEt2, 48%; FC6H4CEt3, 29%.
Entry 11. A 40 µL (326 µmol) volume of substrate 2 was mixed
with 135 µL (987 µmol) of triethylaluminum, 5.0 µL (43 µmol) of
C6F6, and 2.3 mg (3.3 µmol) of Et2Al[HCB11H5Br6] in 0.5 mL of
hexanes in a J. Young tube. A colorless solution with a small
amount of precipitate was formed. An elevation of temperature was
observed. The mixtures were allowed to stay at room temperature
for 24 h. The reactions were monitored by detecting the increase
in the intensity of the 19F NMR resonance of Al-F and decrease
in the intensity of the 19F NMR resonance of F substrates (δ -66.1
(C6H5CF3)). The ratio of products in GC/MS is 16:66:18 C6H5-
CH2CH2CH3:C6H5CHEt2:C6H5-CEt3.
Entry 12. A 40 µL (300 µmol) volume of substrate 3 was mixed
with 125 µL (914 µmol) of triethylaluminum, 5.0 µL (43 µmol) of
C6F6, and 2.1 mg (3.0 µmol) of Et2Al[HCB11H5Br6] in 0.5 mL of
hexanes in a J. Young tube. A colorless solution with a small
amount of precipitate was formed. The mixtures were allowed to
stay at room temperature for 24 h. The reactions were monitored
by detecting the increase in the intensity of the 19F NMR resonance
of Al-F and decrease in the intensity of the 19F NMR resonance
of F substrates (δ -66.0 (ClC6H4CF3). The ratio of products in
GC/MS is 7:71:21 ClC6H4CH2CH2CH3:ClC6H4CHEt2:ClC6H4CEt3.
Entry 13. A 40 µL (315 µmol) volume of substrate 1 was mixed
with 130 µL (950 µmol) of triethylaluminum, 5.0 µL (43 µmol) of
C6F6, and 66 µL of Et2Al[HCB11H5Br6] solution (predissolved in
o-dichlorobenzene, 1 mg/30 µL, 3.2 µmol) in a J. Young tube. A
colorless solution was formed. A dramatic elevation of temperature
was observed. The mixtures were allowed to stay at room
temperature for 24 h. The reactions were monitored by detecting
the increase in the intensity of the 19F NMR resonance of Al-F
and decrease in the intensity of the 19F NMR resonance of F
substrates (δ -65.3 (p-FC6H4CF3), -110.1 (p-FC6H4CF3). Yield
(based on 19F NMR, after 24 h): FC6H4CH2CH2CH3, 13%;
FC6H4CHEt2, 77%; FC6H4CEt3, 7%.
Entry 14. A 40 µL (326 µmol) volume of substrate 2 was mixed
with 135 µL (987 µmol) of triethylaluminum, 5.0 µL (43 µmol) of
C6F6, and 70 µL of Et2Al[HCB11H5Br6] solution (predissolved in
o-dichlorobenzene, 1 mg/30 µL, 3.3 µmol) in a J. Young tube. A
colorless solution was formed. A dramatic elevation of temperature
was observed. The mixtures were allowed to stay at room
temperature for 24 h. The reactions were monitored by detecting
the increase in the intensity of the 19F NMR resonance of Al-F
and decrease in the intensity of the 19F NMR resonance of F
substrates (δ -66.1 (C6H5CF3)). The ratio of products in GC/MS
is 14:71:15 C6H5CH2CH2CH3:C6H5CHEt2:C6H5CEt3.
Entry 20. A 40 µL (260 µmol) volume of substrate 5 was mixed
with 110 µL (804 µmol) of AlEt3, 5.0 µL (43 µmol) of C6F6, and
1.8 mg (2.6 µmol) of Et2Al[HCB11H5Br6] in a J. Young tube. A
clear solution was formed. The mixture was heated at 50 °C for
24 h. The reactions were monitored by detecting the increase in
the intensity of the 19F NMR resonance of Al-F and decrease in
the intensity of the 19F NMR resonance of F substrates (δ -70.2
(C6H5CH2CH2CF3). The ratio of products in GC/MS is 34:30:36
C6H4C5H10:C6H4C7H14:C6H5C7H15.
Entry 21. A 40 µL (260 µmol) volume of substrate 5 was mixed
with 390 µL (780 µmol) of AlMe3 (2 M in hexanes), 5.0 µL (43
µmol) of C6F6,
54 µL of Et2Al[HCB11H5Br6] solution (predis-
and
solved in o-dichlorobenzene, 1 mg/30 µL, 2.6 µmol) in a J. Young
9
11210 J. AM. CHEM. SOC. VOL. 131, NO. 31, 2009