Efficient Procedure for the Synthesis of Crystalline Aryldiazonium Trifluoroacetates
FULL PAPER
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1.61Ϫ1.78 (m, 1 H, 4-H), 2.29Ϫ2.56 (m, 2 H, 5-H), 3.79Ϫ3.90 (m, H), 7.46 (d, 3J ϭ 8.76 Hz, 2 H, 3Ј-H), 7.51 (d, J ϭ 8.20 Hz, 2 H,
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1 H, 3-H), 5.73Ϫ5.78 (m, 1 H, 1-H), 5.90Ϫ5.95 (m, 1 H, 2-H), 6.47
7-H), 7.56 (d, J ϭ 8.80 Hz, 2 H, 4-H), 7.80 (d, J ϭ 8.76 Hz, 2 H,
(br. s, 1 H, NH) 7.11 (d, 3J ϭ 8.40 Hz, 2 H, 3Ј-H), 7.28 (d, 3J ϭ 2Ј-H).
Ϫ
13C NMR (CDCl3): δ ϭ 29.11 [C(CH3)3], 81.64
8.40 Hz, 2 H, 2Ј-H). Ϫ 13C NMR (CDCl3): δ ϭ 29.11 [C(CH3)3], [C(CH3)3], 101.05 (C-3), 111.82 (C-7), 119.27 (C-3Ј), 121.46 (C-4),
33.21 (C-4), 34.60 (C-5), 51.44 (C-3), 81.12 [OC(CH3)3], 119.59 (C- 123.66 (C-5 or C-6), 124.73 (C-5 or C-6), 126.05 (C-9), 126.52 (C-
3Ј), 128.42 (C-2Ј), 132.61 (C-1), 135.12 (C-2), 137.00 (C-4Ј), 142.08 2Ј), 130.13 (C-1Ј), 139.45 (C-4Ј), 153.31 [OC(ϭO)NH], 155.48 (C-
(C-1Ј), 153.59 [OC(ϭO)NH]. Ϫ MS (70 eV); m/z (%): 259 (31)
8), 156.55 (C-2). Ϫ MS (70 eV); m/z (%): 309 (5) [Mϩ], 253.1 (30)
[Mϩ], 203 (100) [Mϩ Ϫ H2CϭCMe2], 159 (10) [MHϩ Ϫ H2Cϭ [Mϩ Ϫ H2CϭCMe2], 235.1 (56) [Mϩ Ϫ HOCMe3], 209.1 (100)
CMe2 Ϫ CO2], 158 (10) [Mϩ Ϫ OϭCOCMe3].
[MHϩ Ϫ H2CϭCMe2 Ϫ CO2].
3-Tolylcyclopentene (17b):[65][66] Colorless liquid.
Ϫ
1H NMR
2-Tolylbenzo[b]furan (19b):[67] Light-yellow crystals, m.p.
128Ϫ129°C (ref. 128Ϫ129°C[68]). Ϫ 1H NMR (CDCl3): δ ϭ 2.46
(s, 3 H, CH3), 7.02 (d, 4J ϭ 0.81 Hz, 1 H, 3-H), 7.26Ϫ7.37 (m, 4 H,
aromatic H), 7.59 (dt, J ϭ 6.84 Hz, J ϭ 1.08 Hz, 1 H, 7-H), 7.64
(dt, 3J ϭ 6.87 Hz, 4J ϭ 1.08 Hz, 1 H, 4-H), 7.83 (d, 3J ϭ 8.22 Hz,
2 H, 2Ј-H). Ϫ 13C NMR (CDCl3): δ ϭ 22.14 (CH3), 101.31 (C-3),
111.85 (C-7), 121.5 (C-4), 123.61 (C-5 or C-6), 124.75 (C-5 or C-
6), 125.64 (C-2Ј), 128.50 (C-8), 130.11 (C-1Ј), 130.23 (C-3Ј), 139.31
(C-4Ј), 155.52 (C-9), 156.95 (C-2). Ϫ MS (70 eV); m/z (%): 208
(100) [Mϩ], 178 (10) [Mϩ Ϫ CO].
(CDCl3): δ ϭ 1.73Ϫ1.83 (m, 1 H, 4-H), 2.39 (s, 3 H, CH3),
2.42Ϫ2.61 (m, 3 H, 4-H and 5-H), 3.89Ϫ3.96 (m, 1 H, 3-H),
5.81Ϫ5.85 (m, 1 H, 1-H), 5.97Ϫ6.01 (m, 1 H, 2-H), 7.13Ϫ7.21 (m,
4 H, aromatic). Ϫ 13C NMR (CDCl3): δ ϭ 21.72 (CH3), 33.24 (C-
5), 34.62 (C-4), 51.68 (C-3), 127.84 (C-3Ј or C-2Ј), 129.80 (C-3Ј or
C-2Ј), 132.42 (C-1), 135.27 (C-2), 136.16 (C-4Ј), 144.25 (C-1Ј). Ϫ
MS (70 eV); m/z (%): 158 (69) [Mϩ], 157 (100) [Mϩ Ϫ H], 143 (91)
[Mϩ Ϫ CH3].
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3-(4Ј-Nitrophenyl)cyclopentene (17c):[12] Yellow liquid. Ϫ H NMR
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(CDCl3): δ ϭ 1.64Ϫ1.77 (m, 1 H, 4-H), 2.40Ϫ2.58 (m, 3 H, 4-H
and 5-H), 3.94Ϫ4.03 (m, 1 H, 3-H), 5.74Ϫ5.77 (m, 1 H, 1-H), 6.03
(dt, 3J ϭ 2.21 Hz, 3JЈ ϭ 5.76 Hz, 1 H, 2-H), 7.36 (d, 2 H, 3J ϭ
2-(4Ј-Nitrophenyl)benzo[b]furan (19c): Yellow crystals, m.p.
177Ϫ178°C (ref. 182Ϫ184°C[69]). Ϫ 1H NMR (CDCl3): δ ϭ 7.25
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(s, 1 H, 3-H), 7.29 (dd, J ϭ 1.28 Hz, 3J ϭ 7.32 Hz, 1 H, 5-H), 7.38
8.79 Hz, 2 H, 2Ј-H), 8.14 (d, 3J ϭ 8.52 Hz, 2 H, 3Ј-H).
Ϫ
(ddd, 3J ϭ 8.04 Hz, 3JЈ ϭ 7.30 Hz, 4J ϭ 1.46 Hz, 1 H, 6-H), 7.57
(ddd, 3J ϭ 8.12 Hz, 4J ϭ 1.93 Hz, 4JЈ ϭ 1.10 Hz, 1 H, 7-H), 7.66
(ddd, 3J ϭ 7.40 Hz, 4J ϭ 1.73 Hz, 4JЈ ϭ 1.10 Hz, 1 H, 4-H), 8.01
13C NMR (CDCl3): δ ϭ 33.21 (C-5), 34.36 (C-4), 51.91 (C-3),
124.44 (C-3Ј), 128.72 (C-2Ј), 133.45 (C-1), 134.26 (C-2), 147.14 (C-
4Ј), 155.12 (C-1Ј). Ϫ MS (70 eV); m/z (%): 189 (95) [Mϩ], 172 (32)
[Mϩ Ϫ OH], 142 (96) [Mϩ Ϫ HNO2].
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(d, J ϭ 9.14 Hz, 2 H, 2Ј-H), 8.32 (d, J ϭ 9.12 Hz, 2 H, 3Ј-H). Ϫ
13C NMR (CDCl3): δ ϭ 105.87 (C-3), 110.58 (C-5), 122.39 (C-4),
124.29 (C-7), 125.07 (C-3Ј), 125.97 (C-2Ј), 126.6 (C-6), 129.40 (C-
8), 137.03 (C-1Ј), 147.97 (C-4Ј), 154.01 (C-2), 156.17 (C-7). Ϫ
4-(Boc-amino)stilbene (18a): White crystals, m.p. 184Ϫ185°C. Ϫ
1H NMR (CDCl3): δ ϭ 1.58 [s, 9 H, C(CH3)3], 7.08 (d, 3J ϭ
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18.24 Hz, 1 H, Cα-H or Cβ-H), 7.09 (d, J ϭ 18.24 Hz, 1 H, Cα-H MS (70 eV); m/z (%): 239 (100) [Mϩ], 209 (20) [Mϩ Ϫ NO], 193
or Cβ-H), 7.29 (m, 1 H, 4Ј-H), 7.38 (d, 3J ϭ 8.97 Hz, 2 H, 3Ј-H),
(10) [Mϩ Ϫ NO2], 165 (18) [Mϩ Ϫ NO2 Ϫ CO].
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7.41 (d, J ϭ 10.50 Hz, 2 H, 3-H), 7.50 (d, J ϭ 10.23 Hz, 2 H, 2-
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Ethyl 4-Styrylcinnamate (20):[61][70] White crystals, 75% from 16a,
H), 7.55 (d, J ϭ 10.23 Hz, 2 H, 2Ј-H). Ϫ 13C NMR (CDCl3): δ ϭ
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m.p. 141Ϫ143°C (lit. 144.5°C[70]). Ϫ H NMR (CDCl3): δ ϭ 1.40
29.08 [C(CH3)3], 81.41 [OC(CH3)3], 119.30 (C-3), 127.09 (C-2Ј),
127.93 (C-2 and Cα-H), 128.10 (C-4Ј), 128.85 (Cβ-H), 129.40 (C-3Ј),
132.96 (C-1), 138.21 (C-1Ј), 138.56 (C-4Ј), 153.37 [OC(ϭO)NH]. Ϫ
MS (70 eV); m/z (%): 295 (12) [Mϩ], 239 (100) [MHϩ Ϫ H2Cϭ
CMe2], 221 (61) [Mϩ Ϫ HOCMe3], 195 (88) [MHϩ Ϫ H2CϭCMe2
Ϫ CO2].
(t, 3J ϭ 7.15 Hz, 3 H, CH2CH3), 4.32 (q, 3J ϭ 7.13 Hz, 2 H,
CH2CH3), 6.49 (d, 3J ϭ 16.02 Hz, 1 H, ϭCHCO), 7.14 (d, 3J ϭ
16.36 Hz, 1 H, C6H5CHϭCH), 7.21 (d, 3J ϭ 16.38 Hz, 1 H,
C6H5CHϭCH), 7.33 (dt, 3J ϭ 6.86 Hz, 4J ϭ 1.50 Hz, 1 H, 4Ј-H),
7.42 (dd, 3J ϭ 6.86 Hz, 4J ϭ 1.60 Hz, 2 H, 3Ј-H), 7.56Ϫ7.60 (m,
6 H, 2Ј-H, 3-H and 2-H), 7.73 (d, 3J ϭ 16.00 Hz, 1 H, CHϭ
CHCO). Ϫ 13C NMR (CDCl3): δ ϭ 15.09 (CH3), 61.25 (CH2),
118.53 (ϭCHCO), 127.42 (C-3Ј), 127.65 (C-2), 128.48 (C6H5CHϭ
CH), 128.77 (C-4Ј), 129.23 (C-3), 130.33 (C-3Ј), 129.50 (C-2Ј),
130.78 (C6H5CHϭCH), 134.35 (C-1), 137.67 (C-1Ј), 140.03 (C-4),
144.80 (CHϭCHCO), 167.82 (CϭO ester). Ϫ MS (70 eV); m/z (%):
279 [MHϩ] (20), 278 (64) [Mϩ], 233 (18) [Mϩ Ϫ OEt], 204 (20)
[Mϩ Ϫ OEt Ϫ CO], 203 (37) [Mϩ Ϫ Ar], 202 (38) [Mϩ Ϫ Ar], 178
(30) [Mϩ Ϫ CH2ϭCHϪCO2Et].
4-Methylstilbene (18b): White crystals, m.p. 118Ϫ119°C (ref.
119°C[61][67]). Ϫ 1H NMR (CDCl3): δ ϭ 2.42 (s, 3 H, CH3), 7.14
(s, 2 H, Hα and Hβ), 7.22 (d, 3J ϭ 8.02 Hz, 2 H, 3-H), 7.32 (t, 3J ϭ
9.20 Hz, 1 H, 4Ј-H), 7.39 (d, 3J ϭ 7.66 Hz, 2 H, 3Ј-H), 7.48 (d,
3J ϭ 8.02 Hz, 2 H, 2-H), 7.56 (d, 3J ϭ 8.04 Hz, 2 H, 2Ј-H). Ϫ
13C NMR (CDCl3): δ ϭ 22.04 (CH3), 127.18 (C-2 and C-2Ј), 128.16
(C-4Ј), 128.45 (Cβ-H), 129.36 (C-3Ј), 129.44 (Cα-H), 130.16 (C-3),
135.30 (C-4), 138.24 (C-1Ј and C-1). Ϫ MS (70 eV); m/z (%): 194
(98) [Mϩ], 179 (99) [Mϩ Ϫ CH3], 178 (100) [Mϩ Ϫ CH4].
Ethyl 4-(3Ј-Cyclopentenyl)cinnamate (21): Yellowish oil, 47% from
17b.
4-Nitrostilbene (18c):[61][67] Pale-yellow crystals, m.p. 155Ϫ156°C
Ϫ
1H NMR (CDCl3): δ ϭ 1.435 (t, 3J ϭ 7.15 Hz, 3 H,
1
3
(ref. 155°C[67]). Ϫ H NMR (CDCl3): δ ϭ 7.14 (d, J ϭ 16.06 Hz,
CH2CH3), 1.69Ϫ1.82 (m, 1 H, 4Ј-Hcis), 2.37Ϫ2.57 (m, 3 H, 4Ј-
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1 H, Hα), 7.29 (d, J ϭ 16.44 Hz, 1 H, Hβ), 7.34Ϫ7.46 (m, 3 H, 3Ј-
3
Htrans and 5Ј-H), 3.87Ϫ3.97 (m, 1 H, 3Ј-H), 4.27 (q, J ϭ 7.11 Hz,
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H, 4Ј-H), 7.57 (d, J ϭ 7.86 Hz, 2 H, 2Ј-H), 7.64 (d, J ϭ 7.86 Hz,
2 H, 2-H), 8.23 (d, 3J ϭ 7.86 Hz, 2 H, 3-H). Ϫ 13C NMR (CDCl3):
δ ϭ 124.92 (C-3), 127.04 (Cα), 127.61 (C-2), 127.81 (C-2Ј and C-
3Ј), 129.66 (C-4Ј), 134.08 (Cβ), 136.94 (C-1Ј), 144.62 (C-1), 147.51
2 H, CH2CH3), 5.77 (dd, 3J ϭ 5.76 Hz, 4J ϭ 2.00 Hz, 1 H, 2Ј-H),
5.98 (dd, 3J ϭ 5.52 Hz, 4J ϭ 2.20 Hz, 1 H, 1Ј-H), 6.41 (d, 3J ϭ
16.04 Hz, 1 H, ϭCHCO), 7.21 (d, 3J ϭ 8.28 Hz, 2 H, 3-H), 7.46
(d, 3J ϭ 8.02 Hz, 2 H, 2-H), 7.68 (d, 3J ϭ 16.04 Hz, 1 H, CHϭ
CHCO). Ϫ 13C NMR (CDCl3): δ ϭ 15.10 (CH2CH3), 33.26 (C-5Ј),
34.40 (C-4Ј), 51.96 (C-3Ј), 61.19 (CH2CH3), 118.08 (ϭCHCO),
128.42 (C-3), 128.98 (C-2), 133.13 (C-1), 133.26 (C-1Ј), 134.46 (C-
(C-4). Ϫ MS (70 eV); m/z (%): 225 (100) [Mϩ], 178 (44) [Mϩ
Ϫ
HNO2].
2-[(4Ј-Boc-amino)phenyl]benzo[b]furan (19a): White crystals, m.p.
208Ϫ210°C. Ϫ 1H NMR (CDCl3): δ ϭ 1.55 [s, 9 H, C(CH3)3], 6.62 2Ј), 145.32 (CHϭCHCO), 149.97 (C-4), 167.96 (CϭO ester). Ϫ
(br. s, 1 H, NH), 6.94 (d, 4J ϭ 0.72 Hz, 1 H, 3-H), 7.22 (d, 3J ϭ
MS (70 eV); m/z (%): 243 (19) [MHϩ], 242 (100) [Mϩ], 213 (83)
7.80 Hz, 2 H, 5-H or 6-H), 7.25 (d, J ϭ 8.00 Hz, 2 H, 5-H or 6- [Mϩ Ϫ C2H5], 197 (142) [Mϩ Ϫ OEt], 181 (33), 169 (69) [Mϩ
Ϫ
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Eur. J. Org. Chem. 1999, 1357Ϫ1366
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