A. Togni et al.
1-Acetoxy-1,3-dihydro-3,3-dimethyl-1,2-benziodoxole (11):[43] 1-Chloro-
1,3,-dihydro-3,3-dimethyl-1,2-benziodoxole (8) (2.02 g, 6.8 mmol) and
AgOAc (1.18 g, 7.1 mmol) were placed under argon. MeCN (20 mL) was
added and the resulting suspension was stirred overnight (15 h) at ambi-
ent temperature in the dark. Filtration under argon of the precipitated
AgCl followed by removal of the solvent and drying under vacuum yield-
ed the title compound 11 as a white solid in quantitative yield. 1H NMR
(300 MHz, CDCl3, 258C): d = 1.51 (s, 6H; CH3), 1.98 (s, 3H; OCOCH3),
sion of CsF (0.003 g, 0.02 mmol, 2 mol% based on 12) in MeCN (2 mL)
was added dropwise via cannula. After the cloudy, orange solution had
been stirred overnight (18 h), about four-fifths of the solvent was re-
moved under vacuum. The resulting crystals were filtered off and washed
with Et2O and pentane. The residue was taken up in CH2Cl2 and filtered.
The mother liquor was concentrated to dryness under vacuum, yielding
the title compound 15 (0.255 g, 0.58 mmol, 50%) as white crystals. M.p.
1568C; 1H NMR (300 MHz, CD2Cl2, 258C): d
= 7.69–7.80 (m, 3H;
CHarom.), 7.86–7.97 ppm (m, 1H; CHarom. ortho to I); 13C NMR (75 MHz,
CD2Cl2, 258C): d = 81.4 (m, C(CF3)2), 107.3 (q, JC,F = 390.0 Hz; ICF3),
110.4 (CI), 123.5 (q, JC,F = 290.6 Hz; C(CF3)2), 128.9 (q, JC,F = 3.0 Hz;
CH ortho to CI), 130.8 (qu, JC,F = 2.6 Hz; CH ortho to CC(CF3)2), 130.9
(CC(CF3)2), 131.4 (CH) , 133.7 ppm (CH); 19F NMR (188 MHz, CD2Cl2,
258C): d = À36.5 (s, JC,F = 384.7 Hz,[43] 3F, ICF3), À76.1 ppm (s, 6F; C-
(CF3)2); IR (neat): n˜ = 1569 (w), 1471 (w), 1445 (w), 1300 (w), 1257 (m),
1228 (w), 1189 (m), 1143 (m), 1116 (s), 1071 (s), 1005 (w), 964 (m), 953
(m), 944 (s), 865 (w), 760 (m), 754 (m), 728 (m), 720 (m), 692 (m), 682
(m), 659 (m), 642 cmÀ1 (m); ESI-HRMS: calcd (m/z) for C10H10F3IO:
460.9061 ([M+Na+]); found 460.9062 ([M+Na+]); elemental analysis:
calcd (%) for C10H4F9IO (438.03): C 27.42, H 0.92, F 39.04, I 28.97;
found: C 27.26, H 1.03, F 39.06, I 29.20.
7.16 (dd, JH,H
=
1.8 Hz, JH,H
=
6.9 Hz, 1H; CHarom.), 7.45 (m, 2H;
CHarom.), 7.78 ppm (dd, JH,H
=
1.5 Hz, JH,H 7.5 Hz, 1H; CHarom.);
=
13C NMR (75 MHz, CDCl3, 258C): d = 21.4 (OCOCH3), 29.2 (C(CH3)2),
84.5 (C(CH3)2), 115.6 (CI), 126.2, 129.8, 129.9, 130.4 (CH), 149.4 (CC-
(CH3)2), 177.3 ppm (CO).
1-Acetoxy-1,3-dihydro-3,3-bis(trifluoromethyl)-1,2-benziodoxole (12): 1-
Chloro-1,3,-dihydro-3,3-bis(trifluoromethyl)-1,2-benziodoxole
(9)
(1.002 g, 2.48 mmol) and AgOAc (0.415 g, 2.49 mmol) were suspended in
MeCN (15 mL). After being stirred overnight (14.5 h) in the dark, the
precipitated AgCl was filtered off under argon and washed with MeCN.
The mother liquor was evaporated to dryness to yield the title compound
12 (1.039 g, 2.43 mmol, 98%) as a white solid. 1H NMR (300 MHz,
CDCl3, 258C): d
7.93 ppm (d, JH,H = 8.4 Hz, 1H; CHarom.); 13C NMR (75 MHz, CDCl3,
258C): d = 20.4 (CH3), 85.7 (m, C(CF3)2), 115.8 (CI), 123.0 (q, JC,F
= 2.18 (s, 3H; CH3), 7.61–7.79 (m, 3H; CHarom.),
1-Trifluoromethyl-1,3-dihydro-5-methyl-3,3-bis(trifluoromethyl)-1,2-ben-
ziodoxole (16): To a solution of 1-acetoxy-1,3-dihydro-5-methyl-3,3-bis-
(trifluoromethyl)-1,2-benziodoxole (13) (0.93 g, 2.10 mmol) in MeCN
(14 mL) was added Me3SiCF3 (0.5 mL, 3.38 mmol, 1.5 equiv) by using a
=
214.3 Hz; CF3), 129.7 (quintet (qu), JC,F
= 2.4 Hz, CH), 130.2, 131.0
(CH), 131.5 (CC(CH3)2), 133.4(CH), 176.5 ppm (CO); 19F NMR
(188 MHz, CDCl3, 258C): d = À75.8 (d, JH,F = 0.8 Hz; CF3).
syringe. To this mixture
a solution of TBAT (0.011 g, 0.022 mmol,
1 mol% based on 13) in MeCN (3 mL) was added dropwise by using a
cannula. After the mixture had been stirred overnight (15 h), half of the
solvent was removed under vacuum and the resulting white crystals were
filtered off, washed with a minimal amount of Et2O, and dried under
vacuum. The white microcrystals were washed two times with a minimal
amount of CH2Cl2 and dried under vacuum to yield the analytically pure
16 (0.371 g, 0.82 mmol, 39%). M.p. 165–1668C; 1H NMR (300 MHz,
CD2Cl2, 258C): d = 2.53 (s, 3H; CH3), 7.57 (m, 2H; CHarom.), 7.71 ppm
(s, 1H; CHarom.); 13C NMR (75 MHz, CD2Cl2, 258C): d = 20.7 (CH3),
81.3 (qu, JC,F = 29.7 Hz; C(CF3)2), 106.6 (CI), 107.2 (q, JC,F = 384.8 Hz;
ICF3), 123.5 (q, JC,F = 290.2 Hz; C(CF3)2), 128.3 (q, JC,F = 2.9 Hz; CH
ortho to CI), 130.8 (CC(CF3)2), 131.4 (qu, JC,F = 2.5 Hz; CH ortho to CC-
(CF3)2), 134.6 (CH), 142.6 ppm (CCH3); 19F NMR (188 MHz, CD2Cl2,
1-Acetoxy-1,3-dihydro-5-methyl-3,3-bis(trifluoromethyl)-1,2-benziodoxole
(13): 1-Chloro-1,3-dihydro-5-methyl-3,3-bis(trifluoromethyl)-1,2-benzio-
doxole (10) (1.00 g, 2.40 mmol) and AgOAc (0.424 g, 2.54 mmol) were
suspended in MeCN (20 mL) and stirred overnight (18 h) in the dark.
The white precipitate was filtered off and washed with MeCN. The
mother liquor was evaporated to dryness to yield product 13 quantitative-
1
ly as white crystals (1.05 g, 2.40 mmol; 99%). H NMR (250 MHz, CDCl3,
258C): d = 2.17 (s, 3H; OCOCH3), 2.51 (s, 3H; CH3), 7.50 (s, 1H;
CHarom.), 7.56 (d, JH,H
=
8.7 Hz, 1H; CHarom.), 7.75 ppm (d, JH,H
=
8.4 Hz, 1H; CHarom.); 13C NMR (63 MHz, CDCl3, 258C):
d
=
20.4
(OCOCH3), 21.0 (CH3), 85.5 (qu, JC,F = 30.6 Hz, C(CF3)2), 112.0 (CI),
123.1 (q, JC,F = 289.2 Hz, CF3), 129.7 (CH), 130.2 (qu, JC,F = 2.3 Hz; CH
ortho to CC(CF3)2), 131.6 (CC(CF3)2), 134.4 (CH), 141.9 (CCH3),
176.5 ppm (CO); 19F NMR (188 MHz, CDCl3, 258C): d = À75.8 ppm (d,
JH,F = 0.9 Hz; CF3).
258C): d = À36.7 (s, JC,F = 384.9 Hz,[43] 3F; ICF3), À76.1 ppm (d, JH,F
=
4.3 Hz, 6F; C(CF3)2); IR (neat): n˜ = 1447 (w), 1261 (m), 1208 (m), 1193
(m), 1170 (m), 1130 (s), 1074 (s), 1015 (m), 978 (m), 962 (s), 950 (m), 892
(m), 838 (m), 804 (s), 748 (m), 731 (m), 718 (m), 688 (m), 679 (m),
658 cmÀ1 (m); ESI-MS (m/z): 474.9 ([M+Na+]), 452.8 ([M+]), 383.9 ([M+
ÀCF3]); elemental analysis: calcd (%) for C11H6F9IO (452.05): C 29.23, H
1.34, F 37.82; found: C 29.19, H 1.36, F 37.78.
1-Trifluoromethyl-1,3-dihydro-3,3-dimethyl-1,2-benziodoxole (14): To
a
solution of 1-acetoxy-1,3,-dihydro-3,3-dimethyl-1,2-benziodoxole (11)
(2.06 g, 6.5 mmol) in MeCN (25 mL), Me3SiCF3 (1.5 mL, 10.15 mmol,
1.5 equiv) was added by using a syringe. A suspension of CsF (0.010 g,
0.066 mmol, 1 mol% based on 11) in MeCN (5 mL) was added dropwise.
The reaction mixture was stirred overnight (16 h) at ambient tempera-
ture. After removal of the solvent and all volatile compounds under
vacuum, pentane (25 mL) was added to the resulting oily brown solid.
The brown precipitate was filtered off under argon and the solvent was
removed from the clear colorless solution under vacuum to yield the title
compound 14 (1.00 g, 3.0 mmol, 46%) as a white solid. Sublimation gave
an analytically pure sample. M.p. 54–568C; 1H NMR (300 MHz, CDCl3,
Ethyl 1-oxo-2-trifluoromethylindane-2-carboxylate (18): To a vigorously
stirred suspension of 1-oxoindane-2-carboxylic acid ethyl ester (17)
(0.041 g, 0.2 mmol), K2CO3 (0.083 g, 0.6 mmol, 3.0 equiv), and nBu4NI
(0.0074 g, 0.02 mmol, 10 mol%) in MeCN (2 mL), solid 14 (0.099 g,
0.3 mmol, 1.5 equiv) was added at ambient temperature. After the mix-
ture had been stirred for 28 h, saturated aqueous NaHCO3 was added.
Extraction of the aqueous phase three times with EtOAc, drying with
MgSO4, filtration, and evaporation of the solvent under reduced pressure
yielded a brownish oil. After purification by chromatography (silica
gel 60; eluent: hexanes/EtOAc (25:1)) 18 (0.036 g, 0.135 mmol, 67%) was
obtained as a colorless oil. 1H NMR (250 MHz, CDCl3, 258C): d = 1.24
(t, JH,H = 7.1 Hz, 3H; CH3), 3.58 (d, JH,H = 17.8 Hz, 1H; CH2), 3.74 (d,
258C): d = 1.46 (s, 6H; CH3), 7.39 (m, 2H; CHarom.), 7.51 ppm (t, JH,H
6.9 Hz, 2H; CHarom.); 13C NMR (75 MHz, CDCl3, 258C): d = 30.8 (C-
(CH3)2), 76.5 (C(CH3)2), 110.7 (q, JC,F = 396.3 Hz; CF3), 110.6 (q, JC,F
=
=
3.0 Hz; CI), 127.3 (CH), 127.8 (q, JC,F = 2.8 Hz, CH), 129.8, 130.6 (CH),
149.2 ppm (CC(CH3)2); 19F NMR (188 MHz, CDCl3, 258C): d = À40.1
(s, JC,F = 396.0 Hz;[43] CF3); IR (neat): n˜ = 2980 (w), 2926 (w), 1563 (w),
1461 (m), 1437 (m), 1376 (m), 1359 (m), 1270 (w), 1248 (m), 1164 (m),
1072 (brs), 1000 (s), 957 (s), 872 (m), 758 (s), 751 (s), 718 (m), 706 (w),
648 (w), 602 cmÀ1 (s); elemental analysis: calcd (%) for C10H10F3IO
(330.09): C 36.39, H 3.05, F 17.27, I 38.45; found: C 36.61, H 3.23, F
17.31, I 38.30.
JH,H
= 17.8 Hz, 1H; CH2), 4.25 (m, 2H; CH2), 7.43–7.55 (m, 2H;
CHarom.), 7.66–8.72 (m, 1H; CHarom.), 7.84 ppm (d, JH,H = 7.8 Hz, 1H;
CHarom.); 13C NMR (63 MHz, CDCl3, 258C): d = 13.8 (CH3), 34.2 (q, JC,F
= 1.9 Hz; CH2), 62.8 (CH2), 63.1 (q, JC,F = 26.0 Hz; C a to CO), 123.5
(q, JC,F
=
281.5 Hz; CF3), 125.6, 126.3, 128.5 (CH), 134.4 (q, JC,F
=
1.6 Hz; C), 136.2 (CH), 151.7 (C), 165.1 (q, JC,F
=
2.2 Hz; COOEt),
193.0 ppm (q, JC,F = 1.0 Hz; CO); 19F NMR (188 MHz, CDCl3, 258C): d
= À69.2 ppm (s, JC,F = 281.5 Hz;[43] CF3); EI-MS: m/z: 272.04 ([M+]),
227.01, 200.08, 199.04, 197.99, 180.06, 178.97 (100%), 168.99, 156.99,
152.5, 150.93, 147.00, 131.03, 109.00, 102.03, 101.01, 76.00, 75.00, 29.04,
1-Trifluoromethyl-1,3-dihydro-3,3-bis(trifluoromethyl)-1,2-benziodoxole
(15): To a solution of 1-acetoxy-1,3,-dihydro-3,3-bis(trifluoromethyl)-1,2-
benziodoxole (12) (0.50 g, 1.17 mmol) in MeCN (5 mL) was added
Me3SiCF3 (0.28 mL, 1.76 mmol, 1.5 equiv) by using a syringe. A suspen-
2584
ꢁ 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Eur. J. 2006, 12, 2579 – 2586