Synlett 2006(14): 2256-2260  
DOI: 10.1055/s-2006-949629
LETTER
© Georg Thieme Verlag Stuttgart · New York

The Gold(I)-Catalyzed Cycloisomerization of 1,6-Enynes to 1,4-Dienes

Sang Ick Lee, Soo Min Kim, Sun Young Kim, Young Keun Chung*
Intelligent Textile System Research Center, and Department of Chemistry, College of Natural Sciences, Seoul National University, Seoul 151-747, Korea
Fax: +82(2)8890310; e-Mail: ykchung@snu.ac.kr;
Further Information

Publication History

Received 17 May 2006
Publication Date:
24 August 2006 (online)

Abstract

Cycloisomerization of 1,6-enynes to 1,4-dienes proceeded smoothly in the presence of a gold(I) catalyst under mild reaction conditions, and cyclized 1,4-dienes were isolated in good yields. The catalytic system can tolerate the oxygen and nitrogen tether in the substrate.

5

Lee, S. I.; Kim, S. M.; Kim, S. Y.; Choi, M. R.; Chung, Y. K., manuscript in preparation.

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General Procedure for Au(I)-Catalzyed Cycloisomerization of 1,6-Enynes to 1,4-Dienes: To a flame-dried 15-mL Schlenk flask capped with a rubber septum, CH2Cl2 (5 mL) was injected via syringe under N2 flow. (PPh3)AuCl (13 mg, 5 mol%) and AgOTf (16 mg, 7 mol%) were added sequentially. The Au solution was stirred for 10 min. An enyne (0.73 mmol) was put into the flask under N2 flow. The reaction was monitored by TLC. After the reactant was disappeared, the solvent was removed under reduced pressure. A flash chromatography on a silica gel eluting with hexane and EtOAc (10:1) gave the product.
4-Methyl- N -(3-methylbut-2-enyl)- N -(3-phenylprop-2-ynyl)benzenesulfonamide ( 1a): 1H NMR (300 MHz, CDCl3): δ = 1.72 (s, 3 H), 1.77 (s, 3 H), 2.34 (s, 3 H), 3.90 (d, J = 7.2 Hz, 2 H), 4.30 (s, 2 H), 5.20 (m, 1 H), 7.05 (m, 2 H), 7.29 (m, 5 H), 7.80 (d, J = 8.0 Hz, 2 H). 13C NMR (75 MHz, CDCl3): δ = 17.9, 21.4, 25.9, 36.3, 44.2, 82.3, 85.4, 118.1, 122.4, 127.9, 128.1, 128.3, 129.4, 131.4, 136.1, 139.0, 143.3. MS (EI): m/z calcd for C21H23N1S1O2: 353.1450; found: 353.1451.
( E )-3-Benzylidene-4-(prop-1-en-2-yl)-1-tosylpyrrolidine ( 2a) (Figure 1): 1H NMR (300 MHz, CDCl3): δ = 1.74 (s, 3 H), 2.42 (s, 3 H), 2.94 (dd, J = 4.3, 11.5 Hz, 1 H), 3.38 (s, 1 H), 3.48 (td, J = 2.7, 17.0 Hz, 1 H), 3.64 (dd, J = 3.4, 11.6 Hz, 1 H), 3.99 (dd, J = 3.1, 17.0 Hz, 1 H), 4.78 (s, 3 H), 4.88 (s, 3 H), 6.03 (t, J = 3.4 Hz, 1 H), 7.22 (m, 1 H), 7.27 (m, 4 H), 7.32 (d, J = 8.0 Hz, 2 H), 7.70 (d, J = 8.3 Hz, 2 H). 13C NMR (75 MHz, CDCl3): δ = 21.4, 21.6, 44.9, 45.4, 47.4, 115.2, 120.9, 125.8, 127.5, 127.8, 128.4, 129.8, 133.2, 137.6, 139.8, 143.6, 143.7. MS (EI): m/z calcd for C21H23N1S1O2: 353.1450; found: 353.1454. The ee value was determined to be 22% by HPLC analysis using a chiral column Chiralcel OD-H (254 nm UV detector, r.t., eluent: 3% i-PrOH in hexane, flow rate: 0.5 mL/min, t R(major) = 34 min and t R(minor) = 40 min]; [α]D 18 +50.32 (c = 1.00 in CHCl3).
7,7-Dimethyl-6-phenyl-3-tosyl-3-azabicyclo[4.1.0]hept-4-ene ( 3a): 1H NMR (300 MHz, CDCl3): δ = 0.81 (s, 3 H), 1.04 (s, 3 H), 1.55 (d, J = 5.6 Hz, 1 H), 2.51 (s, 3 H), 3.62 (dd, J = 5.9, 12.2 Hz, 1 H), 3.79 (d, J = 12.2 Hz, 1 H), 5.16 (d, J = 8.3 Hz, 1 H), 6.67 (d, J = 8.4 Hz, 1 H), 7.16 (d, J = 7.1 Hz, 2 H), 7.25 (m, 1 H), 7.31 (d, J = 7.6 Hz, 2 H), 7.39 (d, J = 7.9 Hz, 2 H), 7.77 (d, J = 8.1 Hz, 2 H). 13C NMR (75 MHz, CDCl3): δ = 16.1, 21.8, 25.0, 27.4, 30.5, 31.1, 39.0, 110.6, 121.7, 126.4, 127.4, 128.6, 128.9, 129.9, 135.1, 142.6, 143.9. MS (EI): m/z calcd for C21H23N1S1O2: 353.1450; found: 353.1446.
2,4,6-Trimethyl- N -(3-methylbut-2-enyl)- N -(3-phenyl-prop-2-ynyl)benzenesulfonamide ( 1b): 1H NMR (300 MHz, CDCl3): δ = 1.69 (s, 3 H), 1.73 (s, 3 H), 2.28 (s, 3 H), 2.65 (s, 6 H), 3.89 (d, J = 7.4 Hz, 2 H), 4.19 (s, 2 H), 5.13 (t, J = 7.4 Hz, 1 H), 6.95 (s, 2 H), 7.31 (m, 5 H). 13C NMR (75 MHz, CDCl3): δ = 18.0, 21.2, 23.1, 26.2, 35.2, 43.6, 77.2, 83.8, 118.5, 122.8, 128.4, 131.9, 132.2, 133.0, 138.9, 140.6. MS (EI): m/z calcd for C23H27N1S1O2: 381.1763; found: 381.1766.
( E )-3-Benzylidene-1-(mesitylsulfonyl)-4-(prop-1-en-2-yl)pyrrolidine ( 2b): 1H NMR (300 MHz, CDCl3): δ = 1.46 (s, 3 H), 2.29 (s, 3 H), 2.63 (s, 6 H), 3.22 (dd, J = 4.2, 11.8 Hz, 1 H), 3.29 (m, 1 H), 3.51 (dd, J = 3.1, 11.8 Hz, 1 H), 3.85 (m, 1 H), 4.00 (m, 1 H), 4.69 (s, 1 H), 4.76 (s, 1 H), 6.14 (t, J = 3.4 Hz, 1 H), 6.94 (s, 2 H), 7.25 (m, 5 H). 13C NMR (75 MHz, CDCl3): δ = 21.08, 21.1, 23.3, 43.9, 45.7, 115.5, 121.5, 125.7, 127.5, 128.5, 131.7, 131.9, 132.1, 137.6, 139.9, 141.0, 142.9, 143.1. MS (EI): m/z calcd for C23H27N1S1O2: 381.1763; found: 381.1766.
( E )-3-Benzylidene-4-(prop-1-en-2-yl)tetrahydrofuran ( 2c): 1H NMR (300 MHz, CDCl3): δ = 1.76 (s, 3 H), 3.22 (s, 1 H), 3.83 (dd, J = 4.0, 11.1 Hz, 1 H), 3.94 (dd, J = 2.7, 11.1 Hz, 1 H,), 4.33 (m, 2 H), 4.81 (s, 1 H), 4.88 (s, 1 H) 6.19 (t, J = 2.7 Hz, 1 H), 7.29 (m, 5 H) 13C NMR (75 MHz, CDCl3): δ = 21.7, 44.6, 66.3, 68.9, 114.2, 124.3, 125.6, 127.4, 128.5, 136.5, 140.1, 145.0. MS (EI): m/z calcd for C14H16O1: 200.1201; found: 200.1202.
N -(But-2-ynyl)-4-methyl- N -(3-methylbut-2-enyl)ben-zenesulfonamide ( 1d): 1H NMR (300 MHz, CDCl3): δ = 1.53 (s, 3 H), 1.66 (s, 3 H), 1.71 (s, 3 H), 2.42 (s, 3 H), 3.78 (d, J = 7.2 Hz, 2 H), 3.99 (d, J = 2.1 Hz, 2 H), 5.10 (t, J = 7.2 Hz, 1 H), 7.30 (d, J = 8.0 Hz, 2 H), 7.74 (d, J = 8.2 Hz, 2 H). 13C NMR (75 MHz, CDCl3): δ = 3.4, 17.9, 21.7, 26.0, 36.2, 44.1, 72.4, 81.4, 118.5, 128.1, 129.4, 136.6, 138.7, 143.2. HRMS (FAB): m/z calcd for C16H21N1S1O2: 292.1371; found: 292.1375.
( E )-3-Ethylidene-4-(prop-1-en-2-yl)-1-tosylpyrrolidine ( 2d): 1H NMR (300 MHz, CDCl3): δ = 1.60 (s, 3 H), 1.72 (s, 3 H), 2.43 (s, 3 H), 2.74 (m, 1 H), 2.93 (dd, J = 4.9, 11.5 Hz, 1 H), 3.30 (m, 1 H), 3.34 (m, 1 H), 3.67 (m, 1 H), 4.78 (s, 1 H), 4.90 (m, 1 H), 5.45 (t, J = 5.6 Hz, 1 H), 7.31 (d, J = 8.1 Hz, 2 H), 7.65 (d, J = 8.3 Hz, 2 H). 13C NMR (75 MHz, CDCl3): δ = 20.5, 21.4, 21.6, 44.9, 47.2, 47.7, 114.3, 118.6, 127.9, 128.0, 129.7, 134.1, 143.6, 144.1. MS (EI): m/z calcd for C16H21N1S1O2: 292.1371; found: 292.1375.
N -(3-Cyclopropylprop-2-ynyl)-4-methyl- N -(3-methyl-but-2-enyl)benzenesulfonamide ( 1e): 1H NMR (300 MHz, CDCl3): δ = 0.29 (m, 2 H), 0.58 (m, 2 H), 0.93 (m, 1 H), 1.62 (s, 3 H) 1.69 (s, 3 H), 2.40 (s, 3 H), 3.75 (d, J = 7.3 Hz, 2 H), 3.97 (d, J = 1.9 Hz, 2 H), 5.08 (t, J = 7.3 Hz, 1 H), 7.25 (d, J = 8.3 Hz, 2 H), 7.69 (d, J = 8.3 Hz, 1 H). 13C NMR (75 MHz, CDCl3): δ = -0.9, 7.8, 17.9, 21.5, 25.9, 36.1, 43.9, 68.2, 89.1, 118.3, 127.9, 129.3, 136.4, 138.6, 143.2. MS (EI): m/z calcd for C18H23N1S1O2: 317.1450; found: 317.1447.
( E )-3-(Cyclopropylmethylene)-4-(prop-1-en-2-yl)-1-tosylpyrrolidine ( 2e): 1H NMR (300 MHz, CDCl3): δ = 0.45 (m, 1 H), 0.56 (m, 1 H), 1.20 (m, 2 H), 1.77 (s, 3 H), 2.41 (s, 3 H), 2.87 (m, 2 H), 3.30 (d, J = 15.9 Hz, 1 H), 3.39 (d, J = 7.6 Hz, 1 H), 3.72 (m, 1 H), 4.83 (s, 1 H), 4.91 (s, 1 H), 5.31 (t, J = 3.3 Hz, 1 H), 7.30 (d, J = 8.5 Hz, 1 H), 7.64 (d, J = 8 3 Hz, 1 H). 13C NMR (75 MHz, CDCl3): δ = 5.6, 6.2, 14.9, 20.8, 21.4, 44.8, 46.6, 47.3, 114.3, 115.1, 127.7, 129.5, 133.4, 139.3, 143.4, 144.4. MS (EI): m/z calcd for C18H23N1S1O2: 317.1450; found: 317.1444.
6-Cyclopropyl-7,7-dimethyl-3-tosyl-3-azabicyclo[4.1.0]hept-4-ene ( 3e): 1H NMR (300 MHz, CDCl3): δ = 0.05 (m, 2 H), 0.42 (m, 2 H), 0.69 (d, J = 6.2 Hz, 1 H), 0.76 (s, 3 H), 0.91 (m, 1 H), 1.14 (s, 3 H), 2.42 (s, 3 H), 3.28 (dd, J = 6.3, 12.2 Hz, 1 H), 3.45 (dd, J = 1.5, 12.2 Hz, 1 H), 4.90 (dd, J = 0.9, 8.5 Hz, 1 H), 6.54 (d, J = 8.5 Hz, 1 H), 7.29 (d, J = 8.1 Hz, 2 H), 7.64 (d, J = 8.3 Hz, 2 H). 13C NMR (75 MHz, CDCl3): δ = 3.5, 4.9, 12.9, 16.5, 21.5, 22.5, 25.4, 29.0, 38.8, 108.8, 121.5, 127.1, 129.6, 135.0, 143.6. MS (EI): m/z calcd for C18H23N1S1O2: 317.1450; found: 317.1447.
N-(3-Cyclohexenylprop-2-ynyl)-4-methyl- N -(3-methylbut-2-enyl)benzenesulfonamide ( 1f): 1H NMR (300 MHz, CDCl3): δ = 1.53 (m, 4 H), 1.67 (s, 3 H), 1.72 (s, 3 H), 1.79 (dd, J = 5.4, 7.3 Hz, 2 H), 2.01 (d, J = 1.7 Hz, 2 H), 2.41 (s, 3 H), 3.80 (d, J = 7.3 Hz, 2 H), 4.16 (s, 2 H), 5.13 (t, J = 7.3 Hz, 1 H), 5.76 (ddd, J = 1.7, 3.8, 5.6 Hz, 1 H), 7.27 (d, J = 8.7 Hz, 2 H), 7.74 (d, J = 8.3 Hz, 1 H). 13C NMR (75 MHz, CDCl3): δ = 18.1, 21.62, 21.69, 22.4, 25.7, 26.1, 29.1, 36.6, 44.2, 79.6, 87.4, 118.4, 120.1, 128.1, 129.5, 135.1, 136.6, 138.9, 143.2. MS (EI): m/z calcd for C21H27N1S1O2: 357.1763; found: 357.1757.
( E )-3-(Cyclohexenylmethylene)-4-(prop-1-en-2-yl)-1-tosylpyrrolidine ( 2f): 1H NMR (300 MHz, CDCl3): δ = 1.53 (m, 2 H), 1.61 (m, 2 H), 1.78 (s, 3 H), 2.06 (m, 4 H), 2.42 (s, 3 H), 2.79 (dd, J = 4.0, 11.4 Hz, 1 H), 3.12 (s, 1 H), 3.35 (d, J = 17.0 Hz, 1 H), 3.64 (dd, J = 2.6, 11.5 Hz, 1 H), 3.93 (d, J = 3.9 Hz, 1 H), 4.71 (s, 1 H), 4.88 (s, 1 H), 5.67 (t, J = 3.5 Hz, 1 H), 5.71 (s, 1 H), 7.30 (d, J = 8.0 Hz, 2 H), 7.66 (d, J = 8.0 Hz, 2 H). 13C NMR (75 MHz, CDCl3): δ = 21.56, 21.62, 22.3, 22.9, 25.8, 25.9, 43.3, 45.3, 47.7, 113.9, 116.9, 124.5, 127.9, 129.7, 133.7, 134.5, 138.3, 143.5, 144.8. MS (EI): m/z calcd for C21H27N1S1O2: 357.1763; found: 357.1765.
N -[3-(4-Methoxyphenyl)prop-2-ynyl]-4-methyl- N -(3-methylbut-2-enyl)benzenesulfonamide ( 1g): 1H NMR (300 MHz, CDCl3): δ = 1.69 (s, 3 H), 1.73 (s, 3 H), 2.33 (s, 3 H), 3.77 (s, 3 H), 3.88 (d, J = 7.3 Hz, 2 H), 4.23 (s, 2 H), 5.16 (t, J = 7.3 Hz, 1 H), 6.75 (d, J = 6.8 Hz, 2 H), 6.99 (d, J = 6.8 Hz, 2 H), 7.23 (d, J = 8.0 Hz, 2 H), 7.76 (d, J = 8.0 Hz, 2 H). 13C NMR (75 MHz, CDCl3): δ = 18.0, 21.5, 26.0, 36.5, 44.2, 55.4, 80.8, 85.4, 113.8, 114.5, 118.3, 127.9, 129.5, 133.0, 136.3, 138.9, 143.3, 159.7. MS (HRFAB): m/z calcd for C22H25N1S1O3: 383.1555; found: 383.1555.
( E )-3-(4-Methoxybenzylidene)-4-(prop-1-en-2-yl)-1-tosylpyrrolidine ( 2g): 1H NMR (300 MHz, CDCl3): δ = 1.74 (s, 3 H), 2.42 (s, 3 H), 2.94 (dd, J = 4.3, 11.6 Hz, 1 H), 3.34 (s, 3 H), 3.48 (m, 1 H), 3.64 (dd, J = 3.2, 11.5 Hz, 1 H), 3.77 (s, 1 H), 3.98 (dd, J = 3.5, 16.8 Hz, 1 H), 4.78 (s, 1 H), 4.88 (s, 1 H), 5.95 (t, J = 3.4 Hz, 1 H), 6.80 (d, J = 9.0 Hz, 2 H), 7.21 (d, J = 8.8 Hz, 2 H), 7.32 (m, 2 H), 7.69 (m, 2 H). 13C NMR (75 MHz, CDCl3): δ = 21.4, 21.7, 45.2, 45.4, 47.6, 55.4, 113.9, 115.2, 119.5, 126.9, 127.9, 129.8, 132.5, 133.7, 137.2, 143.7, 143.9, 159.2. MS (HRFAB): m/z calcd for C22H25N1S1O3: 383.1555; found: 383.1555.
4-Methyl- N -(3-methylbut-2-enyl)- N -[3-(naphthalen-1-yl)prop-2-ynyl]benzenesulfonamide ( 1h): 1H NMR (300 MHz, CDCl3): δ = 1.70 (s, 3 H), 1.77 (s, 3 H), 2.12 (s, 3 H), 3.97 (d, J = 7.2 Hz, 2 H), 4.46 (s, 2 H), 5.24 (t, J = 7.2 Hz, 1 H), 7.14 (d, J = 8.1 Hz, 2 H), 7.33 (m, 2 H), 7.48 (m, 2 H), 7.82 (m, 5 H). 13C NMR (75 MHz, CDCl3): δ = 18.0, 21.3, 26.0, 36.6, 44.3, 83.6, 87.1, 118.1, 120.1, 125.0, 125.9, 126.4, 126.6, 127.8, 128.2, 128.8, 129.5, 130.5, 132.9, 133.0, 135.9, 139.2, 143.4. MS (EI): m/z calcd for C25H25N1S1O2: 403.1606; found: 403.1601.


( E )-3-(Naphthalen-1-ylmethylene)-4-(prop-1-en-2-yl)-1-tosylpyrrolidine ( 2h): 1H NMR (300 MHz, CDCl3): δ = 1.67 (s, 3 H), 2.45 (s, 3 H), 3.23 (dd, J = 4.4, 11.5 Hz, 1 H), 3.46 (s, 1 H), 3.61 (m, 2 H), 4.03 (d, J = 15.1 Hz, 1 H), 4.70 (s, 1 H), 4.72 (s, 1 H), 5.84 (t, J = 2.9 Hz, 1 H), 7.17 (d, J = 6.3 Hz, 1 H), 7.40 (m, 5 H), 7.79 (m, 5 H). 13C NMR (75 MHz, CDCl3): δ = 21.4, 21.7, 45.2, 47.5, 47.6, 114.9, 124.4, 125.2, 125.3, 125.7, 125.8, 125.9, 127.7, 127.9, 128.7, 129.9, 131.3, 133.2, 133.9, 137.7, 138.9, 143.6, 143.8. MS (EI): m/z calcd for C25H25N1S1O2: 403.1606; found: 403.1604.
N -[3-(3,5-Dimethylphenyl)prop-2-ynyl]-4-methyl- N -(3-methylbut-2-enyl)benzenesulfonamide ( 1i): 1H NMR (300 MHz, CDCl3): δ = 1.68 (s, 3 H), 1.72 (s, 3 H), 2.20 (s, 6 H), 2.28 (s, 3 H), 3.88 (d, J = 7.3 Hz, 2 H), 4.27 (s, 2 H), 5.17 (t, J = 7.3 Hz, 1 H), 7.05 (m, 2 H), 7.23 (m, 3 H), 7.77 (d, J = 8.2 Hz, 2 H). 13C NMR (75 MHz, CDCl3): δ = 14.8, 21.8, 27.4, 27.5, 31.1, 40.7, 117.8, 119.8, 126.7, 127.3, 128.6, 129.4, 130.0, 134.8, 140.7, 144.0. MS (EI): m/z calcd for C23H27N1S1O2: 381.1763; found: 381.1762.
( E )-3-(3,5-Dimethylbenzylidene)-4-(prop-1-en-2-yl)-1-tosylpyrrolidine ( 2i): 1H NMR (300 MHz, CDCl3): δ = 1.75 (s, 3 H), 2.26 (s, 6 H), 2.40 (s, 3 H), 2.92 (dd, J = 4.3, 11.6 Hz, 1 H), 3.36 (s, 1 H), 3.46 (dd, J = 2.6, 17.0 Hz, 1 H), 3.64 (dd, J = 3.3, 11.6 Hz, 1 H), 3.96 (dd, J = 3.6, 17.0 Hz, 1 H), 4.76 (s, 1 H), 4.86 (s, 1 H), 5.97 (t, J = 3.4 Hz, 1 H), 6.85 (s, 1 H), 6.87 (s, 2 H), 7.30 (d, J = 8.0 Hz, 2 H), 7.68 (d, J = 8.0 Hz, 2 H). 13C NMR (75 MHz, CDCl3): δ = 21.42, 21.46, 21.6, 45.0, 45.4, 47.5, 115.0, 127.7, 123.7, 127.8, 129.2, 129.7, 133.7, 137.7, 138.0, 140.0, 143.6, 143.8. MS (EI): m/z calcd for C23H27N1S1O2: 381.1763; found: 381.1761.
N -(But-2-enyl)-4-methyl- N -(3-phenylprop-2-ynyl)benzenesulfonamide ( 1k): 1H NMR (300 MHz, CDCl3): δ = 1.72 (d, J = 6.0 Hz, 3 H), 2.33 (s, 3 H), 3.82 (trans) (d, J = 6.6 Hz, 2 H), 3.95 (cis) (d, J = 7.2 Hz, 2 H), 4.30 (s, 2 H), 5.44 (m, 1 H), 5.75 (dt, J = 6.2, 12.8 Hz, 1 H), 7.07 (d, J = 6.6 Hz, 2 H), 7.25 (m, 5 H), 7.77 (d, J = 8.0 Hz, 2 H). 13C NMR (75 MHz, CDCl3): δ = 17.9, 21.6, 36.7, 48.8, 82.1, 85.8, 122.6, 124.9, 128.0, 128.3, 128.5, 129.7, 131.7, 131.8, 136.4, 143.5. MS (EI): m/z calcd for C20H21N1S1O2: 339.1293; found: 339.1296.
7-Methyl-6-phenyl-3-tosyl-3-azabicyclo[4.1.0]hept-4-ene ( 3k): 1H NMR (300 MHz, CDCl3; cis compound): δ = 0.94 (d, J = 6.1 Hz, 3 H), 1.07 (m, 1 H), 1.55 (m, 1 H), 2.43 (s, 3 H), 3.50 (dd, J = 5.4, 11.0 Hz, 1 H), 3.65 (d, J = 11.0 Hz, 1 H), 5.15 (d, J = 8.4 Hz, 1 H), 6.74 (d, J = 8.4 Hz, 1 H), 7.15 (d, J = 6.9 Hz, 2 H), 7.26 (m, 5 H), 7.68 (d, J = 8.2 Hz, 2 H). 1H NMR (300 MHz, CDCl3; trans compound): δ = 0.67 (d, J = 6.3 Hz, 3 H), 1.07 (m, 1 H), 1.68 (m, 1 H), 2.43 (s, 3 H), 3.11 (dd, J = 2.5, 11.5 Hz, 1 H), 4.09 (d, J = 11.5 Hz, 1 H), 5.42 (d, J = 8.1 Hz, 1 H), 6.33 (d, J = 8.1 Hz, 1 H), 7.15 (d, J = 6.9 Hz, 2 H), 7.26 (m, 5 H), 7.70 (d, J = 8.2 Hz, 2 H). 13C NMR (75 MHz, CDCl3): δ = 14.8, 21.8, 27.4, 31.1, 40.7, 117.8, 119.8, 126.7, 127.3, 128.6, 129.4, 130.0, 134.8, 140.7, 144.0. MS (EI): m/z calcd for C20H21N1S1O2: 339.1293; found: 339.1296.