Reactions of Substituted 2-Acetophenone Triflates
3.56 (quint, J ) 8.0 Hz, 1H), 1.88 (m, 4H), 1.71 (m, 2H), 1.61
(m, 2H); 13C NMR (100 MHz, CDCl3) δ 146.8, 133.0, 132.6,
130.4, 128.4, 122.7, 122.6, 120.1, 118.6, 116.1, 49.5, 29.6, 26.1;
IR (cm-1) 2957.9, 2871.6, 1693.5, 1604.7, 1480.9, 1425.4,
1211.4, 1140.9, 999.1, 902.6, 864.2, 779.5; GC-MS m/z 322
(M+, 100).
Exp er im en ta l Section
Gen er a l Meth od for th e P r ep a r a tion of Su bstitu ted
2-Tr iflu or om eth a n esu lfon yl Acetop h en on es. P r ep a r a -
tion of Tr iflu or om eth a n esu lfon ic Acid 2-(Cyclop en t-3-
en eca r bon yl)p h en yl Ester (1g). Cyclopent-3-enyl(2-hydrox-
yphenyl)methanone (564 mg, 3.0 mmol) and pyridine (475 mg,
6.0 mmol) were stirred in CH2Cl2 (15 mL) at -78 °C under
N2. To this solution was added trifluoromethane sulfonic
anhydride (1.02 g, 3.6 mmol) in CH2Cl2 (10 mL) dropwise over
0.5 h. The mixture was allowed to warm to ambient temper-
ature, stirred for 2 h, and then poured into 1 N aqueous HCl
solution (25 mL). The mixture was shaken, the layers were
separated, and the organic layer was washed with 1 N aqueous
HCl solution (2 × 15 mL), H2O (2 × 30 mL), saturated aqueous
NaHCO3 solution (20 mL), and finally, saturated aqueous NaCl
solution (20 mL). The organic layer was dried through a cotton
plug and concentrated to an oil, which was purified by
chromatography on silica gel plug eluting with 10%EtOAc/
hexanes to afford an oil after concentration (808 mg, 84%):
1H NMR (400 MHz, CDCl3) δ 7.74 (dd, J ) 7.8, 1.7 Hz, 1H),
7.56 (ddd, J ) 8.3, 7.4, 1.7 Hz, 1H), 7.45 (dd, J ) 7.8, 1.2 Hz,
1H), 7.30 (d, J ) 8.3 Hz, 1H), 5.62 (br s, 2H), 3.95 (m, 1H),
2.77-2.58 (m, 4H); 13C NMR (100 MHz, CDCl3) δ 201.1, 147.1,
133.5, 132.2, 130.6, 128.9, 128.7, 123.5, 123.1, 120.4, 117.2,
47.3, 36.0; GC-MS m/z 320 (M+, 100); HRMS calcd 321.0408
for C13H12O4F3S, obsd m/z 321.0405 (M + 1)+.
Tr iflu or om et h a n esu lfon ic a cid 2-m et h yl-2-p r op io-
n ylp h en yl ester (1h ): 1H NMR (400 MHz, CDCl3) δ 7.69 (dd,
J ) 7.9, 1.6 Hz, 1H), 7.56 (m, 1H), 7.45 (m, 1H), 7.34 (dd, J )
8.3, 0.8 Hz, 1H), 3.34 (m, 1H), 1.18 (d, J ) 6.6 Hz, 6H); 13C
NMR (100 MHz, CDCl3) δ 146.9, 133.2, 132.2, 130.3, 128.7,
122.9, 39.2, 18.6; GC-MS m/z 296 (M+, 100).
Migr a tion Rea ction (1 f 3) t-Bu OK/THF Con d ition s.
P r ep a r a tion of Tr iflu or om eth a n esu lfon ic Acid 1-(2-Hy-
d r oxyp h en yl)p r op en yl Ester (3b). A solution of trifluo-
romethanesulfonic acid 2-propionylphenyl ester (282 mg, 1.0
mmol) was stirred in anhydrous THF (5 mL) at 0 °C under N2
and treated with t-BuOK (247 mg, 2.2 mmol). After 30 min,
the reaction was judged complete, poured into 1 N aqueous
HCl solution (25 mL) at 0 °C, and extracted with ethyl acetate
(3 × 25 mL). The organic layer was washed with H2O (2 × 25
mL), saturated aqueous NaHCO3 solution (25 mL), and
saturated aqueous NaCl solution (20 mL). The organic layer
was dried through a cotton plug and concentrated to an oil,
which was purified by chromatography on silica gel plug
eluting with 10%EtOAc/hexanes to afford an oil after concen-
tration (271 mg, 96%): 1H NMR (400 MHz, CDCl3) δ 11.09 (s,
OH), 7.66 (dd, J ) 8.2, 1.4 Hz, 1H), 7.59 (ddd, J ) 7.7, 7.0, 1.4
Hz, 1H), 7.05 (dd, J ) 8.5, 1.1 Hz, 1H), 6.99 (dd, J ) 8.5, 7.3
Hz, 1H), 5.32 (dd, J ) 7.0 Hz, 1H), 1.86 (dd, J ) 7.0, 0.8 Hz,
3H), NOE difference experiment: irradiation of δ 5.32 (vinyl
proton) causes 14% enhancement of δ 7.66; IR (cm-1) 3055.8,
2985.9, 1639.7, 1615.8, 1576.2, 1488.3, 1452.2, 1365.0, 1309.5,
1267.8, 1209.9, 1180.7, 1117.2, 1072.9, 1035.0, 985.0, 948.6,
828.8, 782.8, 718.3, 677.2; GC-MS m/z 282 (M+, 100).
Tr iflu or om eth a n esu lfon ic a cid 2-a cetylp h en yl ester
1
(1a ): H NMR (400 MHz, CDCl3) δ 7.81 (dd, J ) 7.9, 1.7 Hz,
1H), 7.59 (m, 1H), 7.48 (m, 1H), 7.33 (d, J ) 8.3 Hz, 1H), 2.63
(s, 3H); 13C NMR (100 MHz, CDCl3) δ 196.9, 147.5, 133.9,
132.3, 131.0, 128.8, 123.0, 29.7; GC-MS m/z 268 (M+, 100).
Tr iflu or om et h a n esu lfon ic a cid 2-p r op ion ylp h en yl
ester (1b): 1H NMR (400 MHz, CDCl3) δ 7.76 (dd, J ) 7.7,
1.7 Hz, 1H), 7.57 (ddd, J ) 8.3, 7.7, 1.7 Hz, 1H), 7.46 (ddd, J
) 7.7, 7.5, 1.0 Hz, 1H), 7.32 (d, J ) 8.3 Hz, 1H), 2.96 (q, J )
7.1 Hz, 2H), 1.21 (t, J ) 7.1 Hz, 3H); 13C NMR (100 MHz,
CDCl3) δ 201.0, 146.8, 133.3, 132.7, 130.2, 128.5, 122.8, 126.3,
123.1, 119.9, 116.7, 35.0, 7.9; IR (cm-1) 3381.9, 3082.2, 2983.5,
2942.6, 2910.2, 1700.5, 1605.8, 1482.2, 1425.9, 1350.1, 1247.9,
1211.6, 1140.4, 1078.1, 956.8, 886.7, 783.7, 789.1; GC-MS m/z
282 (M+); HRMS calcd 283.0252 for C10H10O4F3S, obsd m/z
283.0252 (M+, 100).
Tr iflu or om eth a n esu lfon ic a cid 2-a cetylp h en yl ester
(3a ): 1H NMR (400 MHz, CDCl3) δ 11.41 (s, OH), 7.63 (m, 2H),
7.04 (m, 2H), 4.84 (s, 2H); 13C NMR (100 MHz, CDCl3) δ 163.8,
139.1, 131.7, 120.2, 119.7, 56.7; APCI MS m/z 267 (M - 1);
GC-MS m/z 268+, 100).
Tr iflu or om eth a n esu lfon ic a cid 2-cyclop r op yl-1-(2-h y-
1
d r oxyp h en yl)vin yl ester (3c): H NMR (400 MHz, CDCl3)
δ 11.68 (s, OH), 7.58 (dd, J ) 8.4, 7.3 Hz, 1H), 7.53 (d, J ) 8.3
Hz, 1H), 7.06 (dd, J ) 8.5, 1.0 Hz, 1H), 6.97 (ddd, J ) 8.1, 7.3,
1.0 Hz, 1H), 4.50 (d, J ) 10.7 Hz, 1H), 1.78 (m, 1H), 1.03 (m,
1H), 0.81 (m, 2H), 0.38 (m, 1H); LC-MS m/z 120 (M - 188+,
100).
Tr iflu or om eth an esu lfon ic acid 2-(2-cyclopr opylacetyl)-
p h en yl ester (1c): H NMR (400 MHz, CDCl3) δ 7.73 (dd, J
) 7.7, 1.8 Hz, 1H), 7.56 (ddd, J ) 8.3, 7.4, 1.8 Hz, 1H), 7.45
(ddd, J ) 8.0, 7.4, 1.0 Hz, 1H), 7.32 (d, J ) 8.3 Hz, 1H), 2.83
(d, J ) 6.8 Hz, 2H), 1.10 (m, 1H), 0.57 (m, 2H), 0.15 (dd, J )
10.6, 4.8 Hz, 2H); GC-MS m/z 252 (M+, 100).
1
Cycliza tion Rea ction (1 f 2). P r ep a r a tion of 2,2-
Dim eth ylben zofu r a n -3-on e (2h ). Trifluoromethanesulfonic
acid 2-methyl-2-propionylphenyl ester (1h , 498 mg, 1.68 mmol)
was dissolved in DMF (8.0 mL) and stirred under a N2
atmosphere. DBU (1,8-diazabicyclo[5.4.0]undec-7-ene, 0.63
mL, 4.20 mmol) was added dropwise causing the reaction
solution to become fluorescent green. After being stirred for
12 min, the reaction was judged complete, poured into 1 N
aqueous HCl solution (25 mL) at 0 °C, and extracted with ethyl
acetate (3 × 25 mL). The organic layer was washed with H2O
(2 × 25 mL), saturated aqueous NaHCO3 solution (25 mL),
and saturated aqueous NaCl solution (20 mL). The organic
layer was dried through a cotton plug and concentrated to an
oil, which was purified by chromatography on silica gel plug
eluting with 10% EtOAc/hexanes to afford an oil after con-
centration (222 mg, 81%): 1H NMR (400 MHz, CDCl3) δ 7.65
(dd, J ) 7.5, 1.1 Hz, 1H), 7.59 (m, 1H), 7.06-7.02 (m, 2H),
1.44 (s, 6H); 13C NMR (100 MHz, CDCl3) δ 171.5, 138.3, 125.1,
121.9, 119.8, 113.8, 88.1, 23.2; GC-MS m/z 162 (M+, 83%, see
SI).
Tr iflu or om eth a n esu lfon ic a cid 2-h ep t-6-en oylp h en yl
ester (1d ): 1H NMR (400 MHz, CDCl3) δ 7.75 (dd, J ) 7.7,
1.7 Hz, 1H), 7.57 (ddd, J ) 8.3, 7.3, 1.9 Hz, 1H), 7.47 (br t, J
) 8.0 Hz, 1H), 7.32 (d, J ) 8.3 Hz, 1H), 5.79 (m, 1H), 5.00 (dd,
J ) 17.1, 1.4 Hz, 1H), 4.94 (dd, J ) 10.2, 1.0 Hz, 1H), 2.94 (t,
J ) 7.4 Hz, 2H), 2.06 (m, 2H), 1.74 (m, 2H), 1.45 (m, 2H); 13
C
NMR (100 MHz, CDCl3) δ 146.4, 138.4, 133.3, 130.3, 130.3,
128.5, 128.5, 122.7, 114.8, 41.6, 33.5, 28.3, 23.3; CF3 and
carbonyl residues not observed; IR (cm-1) 2934.0, 1698.5,
1605.5, 1426.7, 1216.6, 1141.1, 888.1, 769.9; GC-MS m/z 267
(M - CF3+, 100).
Tr iflu or om et h a n esu lfon ic a cid 2-(3,7-d im et h yloct -6-
1
en oyl)p h en yl ester (1e): H NMR (400 MHz, CDCl3) δ 7.72
(dd, J ) 7.7, 1.5 Hz, 1H), 7.56 (br t, J ) 8.3 Hz, 1H), 7.45 (br
dd, J ) 7.7, 7.5 Hz, 1H), 7.30 (d, J ) 8.1 Hz, 1H), 5.04 (m,
1H), 2.91 (dd, J ) 16.7, 5.3 Hz, 1H), 2.72 (dd, J ) 16.7, 8.1
Hz, 1H), 2.12 (m, 1H), 1.97 (m, 2H), 1.64 (s, 3H), 1.56 (s, 3H),
1.36 (m, 1H), 1.24 (m, 1H), 0.94 (d, J ) 6.7 Hz, 3H); GC-MS
m/z 378 (M+, 100).
P r ep a r a t ion of 2-Met h ylb en zofu r a n -3-on e (2b ). Tri-
fluoromethanesulfonic acid 2-propionylphenyl ester (1b) (282
mg, 1.0 mmol) was dissolved in DMF (5.0 mL), degassed (3
N2/vacuum cycles), and stirred under a N2 atmosphere. DBU
Tr iflu or om eth a n esu lfon ic a cid 2-cyclop en ta n eca r bo-
n ylp h en yl ester (1f). 1H NMR (400 MHz, CDCl3) δ 7.74 (dd,
J ) 7.7, 1.7 Hz, 1H), 7.56 (ddd, J ) 8.3, 7.5, 1.5 Hz, 1H), 7.46
(ddd, J ) 7.7, 7.5, 1.1 Hz, 1H), 7.32 (dd, J ) 8.3, 1.1 Hz, 1H),
J . Org. Chem, Vol. 68, No. 26, 2003 9969