Synlett 2002(11): 1913-1915
DOI: 10.1055/s-2002-34888
LETTER
© Georg Thieme Verlag Stuttgart · New York

Rh2(OAc)4-Mediated Diazo Decomposition of δ-(N-Tosyl)amino-β-keto-α-diazo Carbonyl Compounds: A Novel Approach to Pyrrole Derivatives

Guisheng Deng, Nan Jiang, Zhihua Ma, Jianbo Wang*
Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, Department of Chemical Biology, College of Chemistry, Peking University, Beijing 100871, P. R. China
Fax: +86(10)62751708; e-Mail: wangjb@pku.edu.cn;
Further Information

Publication History

Received 20 August 2002
Publication Date:
21 October 2002 (online)

Abstract

(N-Tosyl)amino substituted β-keto diazo carbonyl compounds have been prepared by reaction of titanium enolate of β-ketodiazoester or -ketone with an activated N-tosylimine. Rh2(OAc)4-catalyzed reaction of the (N-tosyl)amino substituted α-diazocarbonyl compounds leads to the efficient formation of pyrrole derivatives.

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General procedure for the TiCl4-promoted condensation of α-diazo-β-ketoester 1 with N-tosylimine: To a solution of 2a (10.0 mmol) in anhydrous CH2Cl2 (20 mL) at -41 °C were added dropwise TiCl4 (11.0 mmol) and Et3N (11.0 mmol). After the resulting red-dark solution was stirred at -41 °C for 1 h, a solution of N-tosylimine (4 mmol) in anhydrous CH2Cl2 (4 mL) was added dropwise. The reaction mixture was stirred at -41 °C for 9 h and then was quenched with saturated aqueous NH4Cl (5 mL). The organic layer was separated and the aqueous layer was extracted with CH2Cl2 (2 × 20 mL). The combined organic layers were washed with saturated aqueous NaHCO3 (2 × 20 mL), and then dried over Na2SO4. The product was purified by flash chromatography to yield 3a (Ar = Ph) as white solid (1.03 g, 62%). Mp 140-142 °C; IR (KBr) 3223, 2152, 1748, 1625 cm-1; 1H NMR (200 MHz, CDCl3) δ 1.32 (t, J = 7 Hz, 3 H), 2.37 (s, 3 H), 3.19 (dd, J = 15.6, 5.4 Hz, 1 H), 3.36 (dd, J = 15.6, 8 Hz, 1 H), 4.28 (q, J = 7 Hz, 2 H), 4.76-4.86 (m, 1 H), 5.69 (d, J = 7.8 Hz, 1 H), 7.14-7.20 (m, 7 H), 7.58 (d, J = 8.2 Hz, 2 H); 13C NMR (50 MHz, CDCl3) δ 14.2, 21.4, 46.3, 54.5, 61.6, 76.8, 126.3, 127.0, 127.4, 128.4, 129.2, 137.4, 140.1, 143.0, 161.1, 189.8; MS m/z (FAB): 416 [(M+H)+, 13], 388 (3), 344 (2), 261 (11), 245 (69), 219 (20), 181 (12), 171 (49), 139 (23), 115 (38), 91 (100), 77 (22), 59 (38), 41 (53). Anal. Calcd for C20H21N3O5S: C, 57.82; H, 5.09; N, 10.11. Found: C, 57.85; H, 5.09; N, 10.01.

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General procedure for the diazo decomposition of 3 with catalyst Rh2(OAc)4: A solution of 3a (Ar = Ph, 1.0 mmol) in benzene (30 mL) containing Rh2(OAc)4 (0.01 mmol) was heated under reflux for 10 min. The solution was cooled to room temperature and was concentrated. Purification by flash chromatography provided 4a (Ar = Ph, 75% yield) as white solid.
4a: Mp 138-140 °C; IR (KBr) 3453, 3304, 3278, 1692
cm-1; 1H NMR (200 MHz, CDCl3) δ 1.37 (t, J = 7.2 Hz, 3 H), 4.37 (q, J = 7.2 Hz, 2 H), 6.16 (d, J = 3.2 Hz, 1 H), 7.25-7.79 (m, 5 H), 7.91 (br, s, 1 H), 8.76 (br, d, 1 H); 13C NMR (50 MHz, CDCl3) δ 14.6, 61.2, 95.9, 106.2, 124.9, 128.2, 128.6, 131.1, 136.0, 155.2, 162.0; MS m/z (EI) 231 (M+, 91), 203 (3), 185 (100), 156 (18), 129 (12), 102 (72), 77 (14), 51 (6); Anal. Calcd for C13H13NO3: C, 67.52; H, 5.67; N, 6.06. Found: C, 67.45; H, 5.59; N, 5.91.
4b: Mp 91-93 °C; IR (KBr) 3489, 3310, 1696, 1677 cm-1; 1H NMR (200 MHz, CDCl3) δ 1.37 (t, J = 7.2 Hz, 3 H), 2.43 (s, 3 H), 4.35 (q, J = 7.2 Hz, 2 H), 5.98 (d, J = 2.6 Hz, 1 H), 7.23-7.37(m, 4 H), 7.76 (br, s, 1 H), 8.11 (br, s, 1 H); 13C NMR (50 MHz, CDCl3) δ 14.5, 20.7, 60.0, 98.8, 105.5, 126.0, 128.3, 128.4, 130.9, 131.5, 135.7, 135.9, 153.7(br), 162.0(br); MS m/z (EI) 245 (M+, 100), 222 (3), 199 (93), 193 (28), 171 (12), 144 (12), 134 (12), 123 (28), 116 (63), 95 (7), 91 (6), 77 (6), 57 (6), 43 (7). Anal. Calcd for C14H15NO3: C, 68.56; H, 6.16; N, 5.71. Found: C, 68.45; H, 6.18; N, 5.61.
4c: Mp 203 °C; IR (KBr) 3501, 3337, 2227, 1669 cm-1; 1H NMR (200 MHz, CDCl3/DMSO-d 6 ) δ 1.41 (t, J = 7.2 Hz, 3 H), 4.39 (q, J = 7.2 Hz, 2 H), 6.17 (d, J = 2.8 Hz, 1 H), 7.44-7.56 (m, 2 H), 7.89-7.95 (m, 2 H), 8.15 (s, 1 H), 10.91 (br, s, 1 H); 13C NMR (50 MHz, CDCl3/DMSO-d 6 ) δ 14.1, 59.4, 95.7, 106.9, 112.0, 118.1, 128.0, 128.9, 129.9, 132.2, 132.5, 152.7, 161.4; MS m/z (EI) 256 (M+, 14), 241 (2), 210 (20), 178 (5), 171 (43), 155 (57), 127 (14), 107 (22), 91 (100), 65 (39), 57 (31), 39 (18); Anal. Calcd for C14H12N2O3: C, 65.62; H, 4.72; N, 10.93. Found: C, 65.81; H, 4.59; N, 10.83.
4d: Mp 150-152 °C; IR (KBr) 3269, 1680, 1661 cm-1; 1H NMR (200 MHz, CDCl3/DMSO-d 6 ) δ 1.37 (t, J = 7.2 Hz,
3 H), 4.34 (q, J = 7.2 Hz, 2 H), 5.94 (d, J = 2.8 Hz, 1 H), 6.88 (d, J = 16.4 Hz, 1 H), 7.06 (d, J = 16.4 Hz, 1 H), 7.21-7.44 (m, 5 H), 7.91 (s, 1 H), 11.0 (br s, 1 H); 13C NMR (50 MHz, CDCl3/DMSO-d 6 ) δ 14.0, 58.9, 94.8, 105.2, 117.6, 125.4, 126.9, 127.9, 128.3, 133.8, 136.0, 152.6, 161.1; MS m/z (EI) 257 (M+, 100), 210 (88), 183 (11), 182 (6), 167 (8), 154 (28), 128 (46), 102 (5), 77 (6), 51 (5), 29 (5); Anal. Calcd for C15H15NO3: C, 70.02; H, 5.88; N, 5.44. Found: C, 70.22; H, 6.08; N, 5.29.
4e: Mp 131-133 °C; IR (KBr) 3306, 1667, 1564 cm-1; 1H NMR (200 MHz, CDCl3) δ 1.38 (t, J = 7.2 Hz, 3 H), 4.38 (q, J = 7.2 Hz, 2 H), 6.06 (d, J = 2.6 Hz, 1 H), 6.45-6.47 (m, 1 H), 6.56 (d, J = 3.4 Hz, 1 H), 7.41-7.42 (m, 1 H), 7.92 (br s, 1 H), 8.59 (br s, 1 H); 13C NMR (50 MHz, CDCl3) δ 14.5, 60.1, 94.6, 105.4, 106.2, 111.7, 126.8, 142.0, 146.5, 154.4, 162.1; MS m/z (EI) 221 (M+, 95), 193.3 (4), 175 (100), 147 (26), 139 (2), 119 (15), 92 (52), 91 (8), 63 (15), 39 (12); Anal. Calcd for C11H11NO4: C, 59.73; H, 5.01; N, 6.33. Found: C, 59.65; H, 4.97; N, 6.13.
4f: Mp 129-130 °C; IR (KBr) 3502, 3289, 1677, 1574, 1539 cm-1; 1H NMR (200 MHz, CDCl3) δ 1.38 (t, J = 7.2 Hz, 3 H), 4.37 (q, J = 7.2 Hz, 2 H), 5.99 (d, J = 3Hz, 1 H), 6.93-7.26 (m, 2 H), 8.08 (br s, 1 H), 8.84 (br, s, 1 H); 13C NMR (50 MHz, CDCl3) δ 14.5, 60.3, 96.6, 123.7, 127.9, 129.7, 130.7, 131.9, 139.0, 144.5, 160.9; MS m/z (EI) 317 (M+, 80Br, 74), 315 (M+, 78Br, 71), 271 (100), 242 (12), 215 (9), 188 (37), 162 (76), 155 (17), 133 (14), 108 (19), 91 (40), 82 (9), 63 (14), 45 (5); Anal. Calcd for C11H10BrNO3S: C, 41.79; H, 3.19; N, 4.43. Found: C, 41.85; H, 3.26; N, 4.40.
4g: Mp 139-142 °C; IR (KBr) 3320, 1590, 1567 cm-1; 1H NMR (200 MHz, CDCl3) δ 6.14 (d, J = 2.4 Hz, 1 H), 6.50 (dd, J = 3.5, 1.7 Hz, 1 H), 6.66 (d, J = 3.5 Hz, 1 H), 7.44 (d, J = 1.7 Hz, 1 H), 7.50-7.59 (m, 3 H), 7.77-7.82 (m, 2 H), 8.26 (br s, 1 H), 10.43 (br s, 1 H); 13C NMR (50 MHz, CDCl3) δ 94.8, 108.2, 112.1, 116.0, 127.5, 129.0, 129.8, 131.6, 137.7, 142.7, 145.9, 159.3, 184.0; MS m/z (EI) 253 (M+, 100), 236 (5), 224 (4), 196 (4), 176 (30), 147 (7), 120 (9), 105 (37), 92 (24), 91 (3), 77 (49), 65 (20), 51 (17), 39 (15); Anal. Calcd for C15H11NO3: C, 71.14; H, 4.38; N, 5.53. Found: C, 70.98; H, 4.37; N, 5.46.
4h: Mp 159-161 °C; IR (KBr) 3322, 2261, 1626, 1592, 1550, 1503 cm-1; 1H NMR (200 MHz, CDCl3) δ 6.10 (d, J = 2 Hz, 1 H), 6.79 (d, J = 16.5 Hz, 1 H), 7.00 (d, J = 16.5 Hz, 1 H), 7.28-7.54 (m, 8 H), 7.68-7.72 (m, 2 H), 8.41 (br s, 1 H), 10.40 (br s, 1 H); 13C NMR (50 MHz, CDCl3) δ 96.3, 116.6, 117.3, 126.6, 127.5, 128.5, 128.8, 128.9, 131.6, 132.0, 135.9, 137.7, 138.0, 159.5, 183.8; MS m/z (EI) 289 (M+, 100), 288 (27), 270 (10), 212 (13), 156 (6), 128 (23), 105 (49), 77 (31), 51 (7); Anal. Calcd for C19H15NO2: C, 78.87; H, 5.23; N, 4.84. Found: C, 78.80; H, 5.21; N, 4.74.
4i: Mp 178-180 °C(decomposed); IR (KBr) 3272, 1614, 1585, 1534 cm-1; 1H NMR (200 MHz, CDCl3) δ 2.48 (s, 3 H), 3.85 (s, 3 H), 6.01 (d, J = 2.8 Hz, 1 H), 6.93 (d, J = 8.6 Hz, 2 H), 7.62 (d, J = 8.6 Hz, 2 H), 9.47 (br s, 1 H), 10.59 (br, s, 1 H); MS m/z (EI) 231 (M+, 100), 216 (93), 202 (9), 188 (5), 174 (8), 161 (15), 146 (4), 133 (18), 118 (7), 117 (8), 102 (3), 89 (12), 77 (4), 63 (6), 43 (13); Anal. Calcd for C13H13NO3: C, 67.52; H, 5.67; N, 6.06. Found: C, 67.41; H, 5.71; N, 6.01.

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p-Toluenesufinic acid was further converted to thiosulfonic ester, which is isolated and characterized.