Synlett 2007(11): 1759-1762  
DOI: 10.1055/s-2007-982578
CLUSTER
© Georg Thieme Verlag Stuttgart · New York

Au(I)-Catalyzed Annulation of 2-Tosylaminobenzaldehyde and Alkynes

Rachid Skouta, Chao-Jun Li*
Department of Chemistry, McGill University, 801 Sherbrooke St. West, Montreal, QC, H3A 2K6, Canada
e-Mail: cj.li@mcgill.ca;
Further Information

Publication History

Received 1 March 2007
Publication Date:
25 June 2007 (online)

Abstract

2,3-Dihydro-1-tosylquinolin-4(1H)-one derivatives, azaisoflavanones, have been synthesized efficiently via a gold-catalyzed annulation of 2-tosylaminobenzaldehyde and alkynes. This annulation offers the synthesis of a range of potentially bioactive molecules.

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Typical Experimental Procedure for the Synthesis of 3c-j: AuCN (0.6 mg, 0.0025 mmol) and PBu3 (15.4 µL, 0.0625 mmol), aldehyde 1c (0.125 mmol) and alkyne 2a-h (0.187 mmol) in anhyd toluene (0.5-1 mL) was heated in a sealed tube at 150 °C for 2.5 d under nitrogen. The reaction mixture was cooled to r.t. and the solvent was evaporated in vacuo. The residue was purified by flash-column chromatography on silica gel with the appropriate mixture of hexane and EtOAc to give azaisoflavanones 3c-j.
Compound 3c: IR (neat, NaCl): 1691, 1598, 1494, 1476, 1459, 1356, 1294, 1186, 1168, 1090, 970, 908, 844, 814, 769, 751, 699, 671 cm-1. 1H NMR (400MHz, CDCl3): δ = 8.04 (dd, J = 1.6, 8.0 Hz, 1 H), 7.90 (d, J = 8.8 Hz, 1 H), 7.57-7.62 (m, 3 H), 7.25-7.36 (m, 6 H), 7.01 (dd, J = 1.6, 8.0 Hz, 2 H), 4.59 (dd, J 3ax,2eq = 14.0 Hz, J 3ax,2ax = 5.2 Hz, 1 H, H-3ax), 4.10 (dd, J 2eq,3ax = 14.0 Hz, J 2eq,2ax = 12.8 Hz, 1 H, H-2eq), 3.53 (dd, J 2ax,2eq = 12.8 Hz, J 2ax,3ax = 5.2 Hz, 1 H, H-2ax), 2.42 (s, 3 H). 13C NMR (75 MHz, CDCl3): δ = 193.75, 144.97, 142.61, 137.08, 136.07, 134.97, 130.41, 129.14, 128.84, 128.66, 128.04, 127.27, 125.64, 125.456, 123.88, 52.61, 52.28, 21.83. MS (EI): m/z (%) = 377 [M+], 273 (100), 220, 209, 165, 132, 105, 91, 65, 51. HRMS: m/z calcd for C22H19NO3S: 377.10787; found: 377.10797.
Compound 3d: IR (neat, NaCl): 1691, 1599, 1515, 1476, 1459, 1357, 1167, 1118, 1089, 911, 851, 816, 763, 715, 660, 575 cm-1. 1H NMR (400 MHz, CDCl3): δ = 8.03 (dd, J = 2.0, 8.0 Hz, 1 H), 7.91 (d, J = 8.0 Hz, 1 H), 7.57-7.62 (m, 3 H), 7.25-7.29 (m, 3 H), 7.14 (d, J = 8.0 Hz, 2 H), 6.89 (d, J = 7.6 Hz, 2 H), 4.57 (dd, J 3ax,2eq = 14.0 Hz, J 3ax,2ax = 5.2 Hz, 1 H, H-3ax), 4.08 (dd, J 2eq,3ax = 14.0 Hz, J 2eq.2ax = 12.8 Hz, 1 H, H-2eq), 3.49 (dd, J 2ax,2eq = 12.8 Hz, J 2ax,3ax = 5.2 Hz, 1 H, H-2ax), 2.42 (s, 3 H), 2.33 (s, 3 H). 13C NMR (75 MHz, CDCl3): δ = 193.96, 144.92, 142.59, 137.77, 137.07, 134.91, 132.97, 130.37, 129.58, 128.65, 127.25, 125.66, 125.53, 123.88, 52.62, 51.90, 21.83, 21.33. MS (EI): m/z (%) = 391 [M+], 273, 236, 219, 199, 180, 155, 125, 97, 91 (100), 57, 43. HRMS: m/z calcd for C23H21NO3S: 391.12422; found: 391.12452.
Compound 3e: IR (neat, NaCl): 1691, 1598, 1487, 1476, 1458, 1356, 1293, 1167, 1089, 910, 836, 759, 727, 698, 564 cm-1. 1H NMR (400 MHz, CDCl3): δ = 8.05 (d, J = 7.6 Hz, 1 H), 7.92 (d, J = 8.4 Hz, 1 H), 7.46-7.64 (m, 7 H), 7.44 (t, J = 6.4 Hz, 2 H), 7.25-7.37 (m, 4 H), 7.09 (d, J = 6.8 Hz, 2 H), 4.63 (dd, J 3ax,2eq = 14.0 Hz, J 3ax,2ax = 4.8 Hz, 1 H, H-3ax), 4.07 (dd, J 2eq,3ax = 14.0 Hz, J 2eq,2ax = 12.8 Hz, 1 H, H-2eq), 3.58 (dd, J 2ax,2eq = 12.8 Hz, J 2ax,3ax = 4.8 Hz, 1 H, H-2ax), 2.42 (s, 3 H). 13C NMR (75 MHz, CDCl3): δ = 193.82, 145.02, 142.61, 141.06, 140.81, 137.03, 135.06, 134.99, 130.44, 129.25, 129.04, 128.71, 127.91, 127.67, 127.34, 127.26, 125.62, 125.59, 123.92, 52.58, 51.96, 21.87. MS (EI): m/z (%) = 453 [M+], 437, 334, 298, 273, 241, 209, 180 (100), 152, 132, 91, 77. HRMS: m/z calcd for C28H23NO3S: 453.13917; found: 453.13929.
Compound 3f: IR (neat, NaCl): 1691, 1598, 1476, 1458, 1357, 1297, 1167, 1090, 909, 778, 759, 732, 710, 663, 566 cm-1. 1H NMR (500 MHz, CDCl3): δ = 8.10 (d, J = 7.5 Hz, 1 H), 7.96 (d, J = 8.5 Hz, 1 H), 7.88 (d, J = 8.5 Hz, 1 H), 7.81 (d, J = 7.5 Hz, 1 H), 7.65-7.67 (m, 3 H), 7.30-7.47 (m, 7 H), 7.13 (d, J = 7.0 Hz, 1 H), 4.67 (dd, J 3ax,2eq = 13.5 Hz, J 3ax,2ax = 4.0 Hz, 1 H, H-3ax), 4.13-4.33 (m, 2 H, H-2eq, H-2ax), 2.45 (s, 3 H). 13C NMR (75 MHz, CDCl3): δ = 194.01, 145.01, 142.66, 137.31, 135.09, 134.32, 132.72, 131.74, 130.51, 129.46, 128.83, 128.75, 127.29, 126.67, 126.62, 126.13, 126.05, 125.91, 125.69, 124.50, 123.34, 52.02, 49.27, 21.90. MS (EI): m/z (%) = 427 [M+], 273, 244, 215, 202, 154 (100), 141, 128, 91. HRMS: m/z calcd for C26H21NO3S: 427.12352; found: 427.12357.
Compound 3g: IR (neat, NaCl): 1691, 1598, 1514, 1458, 1355, 1296, 1252, 1166, 1089, 1032, 830, 763, 715, 659, 575 cm-1. 1H NMR (400 MHz, CDCl3): δ = 8.02 (d, J = 8.0 Hz, 1 H), 7.89 (d, J = 8.4 Hz, 1 H), 7.56-7.62 (m, 3 H), 7.25-7.29 (m, 3 H), 6.85-6.94 (m, 4 H), 4.56 (dd, J 3ax,2eq = 14.0 Hz, J 3ax,2ax = 5.2 Hz, 1 H, H-3ax), 4.06 (dd, J 2eq,3ax = 14.0 Hz, J 2eq,2ax = 12.8 Hz, 1 H, H-2eq), 3.79 (s, 3 H), 3.48 (dd, J 2ax,2eq = 12.8 Hz, J 2ax,3ax = 5.2 Hz, 1 H, H-2ax), 2.42 (s, 3 H). 13C NMR (75 MHz, CDCl3): δ = 194.17, 159.34, 144.98, 142.57, 137.03, 134.98, 130.42, 129.88, 128.68, 127.97, 127.24, 125.57, 123.88, 114.61, 55.53, 52.69, 51.47, 21.88. MS (EI): m/z (%) = 407 [M+](100), 399, 273, 252, 209, 180, 165, 134, 121, 91, 77. HRMS: m/z calcd for C23H21NO4S: 407.11844; found: 407.11833. Compound 3h: IR (neat, NaCl): 1693, 1599, 1493, 1475, 1458, 1355, 1293, 1236, 1168, 1088, 995, 757, 719, 670, 567 cm-1. 1H NMR (400 MHz, CDCl3): δ = 8.01 (dd, J = 1.6, 7.6 Hz, 1 H), 7.90 (d, J = 8.4 Hz, 1 H), 7.58-7.61 (m, 3 H), 7.25-7.32 (m, 4 H), 7.08 (d, J = 8.0 Hz, 1 H), 6.90-6.97 (m, 2 H), 5.03 (m, 2 H), 4.53 (dd, J 3ax,2eq = 14.4 Hz, J 3ax,2ax = 5.6 Hz, 1 H, H-3ax), 4.16 (dd, J 2eq,3ax = 14.4 Hz, J 2eq,2ax = 12.8 Hz, 1 H, H-2eq), 3.67 (dd, J 2ax,2eq = 12.8 Hz, J 2ax,3ax = 5.6 Hz, 1 H, H-2ax), 3.34 (s, 3 H), 2.40 (s, 3 H). 13C NMR (125 MHz, CDCl3): δ = 193.65, 154.78, 144.76, 142.38, 137.25, 134.55, 130.94, 130.31, 129.50, 128.25, 127.28, 126.57, 125.91, 125.52, 124.81, 122.28, 114.47, 94.39, 56.36, 50.93, 49.45, 21.84. MS (EI): m/z (%) = 437 [M+](100), 318, 282, 273, 238, 220, 209, 180, 164, 132, 119, 91. HRMS: m/z calcd for C24H23NO5S: 437.12900; found: 437.12924.
Compound 3i: IR (neat, NaCl): 1691, 1598, 1513, 1476, 1458, 1355, 1236, 1236, 1167, 1080, 999, 764, 715, 659, 574 cm-1. 1H NMR (400 MHz, CDCl3): δ = 8.02 (d, J = 8.0 Hz, 1 H), 7.90 (d, J = 8.8 Hz, 1 H), 7.57-7.62 (m, 3 H), 7.25-7.29 (m, 3 H), 7.07 (d, J = 8.8 Hz, 2 H), 6.92 (d, J = 8.8 Hz, 2 H), 5.16 (s, 2 H), 4.56 (dd, J 3ax,2eq = 14.0 Hz, J 3ax,2ax = 4.8 Hz, 1 H, H-3ax), 4.05 (dd, J 2eq,3ax = 14.0 Hz, J 2eq,2ax = 12.8 Hz, 1 H, H-2eq), 3.45-3.50 (m, 4 H, H-2ax), 2.42 (s, 3 H). 13C NMR (125 MHz, CDCl3): δ = 194.00, 157.03, 144.97, 142.56, 137.06, 134.96, 130.40, 129.90, 129.22, 128.67, 127.25, 125.58, 125.55, 123.90, 116.92, 94.61, 56.21, 52.65, 51.51, 21.84. MS (EI): m/z (%) = 437 [M+](100), 318, 282, 273, 238, 220, 209, 180, 164, 132, 119, 91. HRMS: m/z calcd for C24H23NO5S: 437.12900; found: 437.12924.
Compound 3j: IR (neat, NaCl): 1691, 1598, 1490, 1476, 1458, 1356, 1166, 1089, 1011, 815, 762, 677, 650, 568 cm-1. 1H NMR (400 MHz, CDCl3): δ = 8.02 (d, J = 8.0 Hz, 1 H), 7.89 (d, J = 8.4 Hz, 1 H), 7.59 (d, J = 8.0 Hz, 2 H), 7.45 (d, J = 8.4 Hz, 2 H), 7.25-7.34 (m, 4 H), 6.89 (d, J = 8.4 Hz, 2 H), 4.55 (dd, J 3ax,2eq = 14.4 Hz, J 3ax,2ax = 5.2 Hz, 1 H, H-3ax), 4.07 (dd, J 2eq,3ax = 14.4 Hz, J 2eq,2ax = 12.8 Hz, 1 H, H-2eq), 3.52 (dd, J 2ax,2eq = 12.8 Hz, J 2ax,3ax = 5.2 Hz, 1 H, H-2ax), 2.42 (s, 3 H). 13C NMR (75 MHz, CDCl3): δ = 193.22, 145.10, 142.56, 136.93, 135.20, 134.94, 132.30, 130.52, 130.45, 128.71, 127.21, 125.62, 125.31, 123.77, 122.16, 52.33, 51.70, 21.87. MS (EI): m/z (%) = 455 [M+], 338, 302, 273 (100), 220, 209, 182, 139, 129, 91, 77. HRMS: m/z calcd for C22H18BrNO3S: 455.01838; found: 455.01759.