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DOI: 10.1055/s-2002-34888
Rh2(OAc)4-Mediated Diazo Decomposition of δ-(N-Tosyl)amino-β-keto-α-diazo Carbonyl Compounds: A Novel Approach to Pyrrole Derivatives
Publication History
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.
Key words
pyrroles - diazo compounds - Ti(IV) enolate - nucleophilic additions - Rh(II) carbene
- 1
Comprehensive
Heterocyclic Chemistry
Vol. 2:
Bird CW. Pergamon Press; Oxford: 1996. - For recent examples of pyrrole syntheses based on Paal-Knorr reaction, see:
-
2a
Hewton CE.Kimber MC.Taylor DK. Tetrahedron Lett. 2002, 43: 3199 -
2b
Takaya H.Kojima S.Murahashi S.-I. Org. Lett. 2001, 3: 421 -
2c
Braun RU.Zeitler K.Muller TJJ. Org. Lett. 2001, 3: 3297 -
2d
Surya Prakash Rao H.Jothilingam S. Tetrahedron Lett. 2001, 42: 6595 - For recent examples of pyrrole syntheses that are not based on Paal-Knorr reaction, see:
-
3a
Chen N.Lu Y.Gadamasetti K.Hurt CR.Norman MH.Fotsch C. J. Org. Chem. 2000, 65: 2603 -
3b
Katritzky AR.Huang T.-B.Voronkov MV.Wang M.Kolb H. J. Org. Chem. 2000, 65: 8819 -
3c
Gabriele B.Salerno G.Fazio A.Bossio MR. Tetrahedron Lett. 2001, 42: 1339 -
3d
Kel’in AV.Sromek AW.Gevorgyan V. J. Am. Chem. Soc. 2001, 123: 2074 -
3e
Allin SM.Barton WRS.Bowman WR.McInally T. Tetrahedron Lett. 2001, 42: 7887 -
3f
Lagu B.Pan M.Wachter MP. Tetrahedron Lett. 2001, 42: 6027 - 4
Doyle MP.McKervey MA.Ye T. Modern Catalytic Methods for Organic Synthesis with Diazo Compounds Wiley Interscience; New York: 1998. -
5a
Calter MA.Sugathapala PM.Zhu C. Tetrahedron Lett. 1997, 38: 3837 -
5b
Calter MA.Sugathapala PM. Tetrahedron Lett. 1998, 39: 8813 -
5c
Calter MA.Zhu C. J. Org. Chem. 1999, 64: 1415 - For examples of intramolecular N-H bond insertion, see:
-
7a
Moyer MP.Feldman PL.Rapoport H. J. Org. Chem. 1985, 50: 5223 -
7b
Wang J.Hou Y. J. Chem. Soc., Perkin Trans. 1 1999, 2277
References
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.
8General 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.
p-Toluenesufinic acid was further converted to thiosulfonic ester, which is isolated and characterized.