Y.-Y. Chen et al. / Tetrahedron 71 (2015) 6210e6218
6215
J¼8.1, 1.9 Hz, 1H), 5.20 (s, 2H), 2.45 (s, 3H), 1.30 (s, 9H); 13C NMR
63%); mp 129e133 ꢀC; 1H NMR (300 MHz, CDCl3)
d
7.87 (d,
(75 MHz, CDCl3)
d
158.0,153.4,147.6, 144.5,133.1,130.7, 129.3,128.9,
J¼8.1 Hz, 2H), 7.34 (d, J¼8.1 Hz, 2H), 7.23 (d, J¼8.4 Hz, 1H), 6.46
(dd, J¼8.4, 2.1 Hz, 1H), 6.36 (dt, J¼10.5, 2.1 Hz, 1H), 6.23 (d,
J¼2.1 Hz, 1H), 5.41 (d, J¼2.4 Hz, 1H), 5.34 (d, J¼10.5 Hz, 1H), 5.10
(d, J¼1.8 Hz, 1H), 3.75 (s, 3H), 2.46 (s, 3H); 13C NMR (75 MHz,
122.7, 118.9, 113.0, 111.1, 61.7, 34.9, 31.4, 22.0; IR (KBr)
n 2067, 1583,
1397 cmꢂ1
;
HRMS (MALDI) calcd for C20H24N3O3S [MþH]þ
386.1533, found 386.1536.
CDCl3)
d 163.0, 162.1, 144.0, 143.1, 138.4, 129.9, 127.5, 121.9, 116.5,
4.3.12. 4-(3-Methylthiophenoxymethyl)-1-tosyl-1H-1,2,3-triazole
108.5, 103.6, 96.4, 89.6, 55.8, 21.8; IR (KBr) n ;
3277, 1621, 1494 cmꢂ1
(1l). White solid (610 mg, 1.626 mmol, 96%); mp 117e119 ꢀC; 1H
HRMS (APCI) calcd for C17H18NO4S [MþH]þ 332.0957, found
NMR (300 MHz, CDCl3)
d
8.19 (s, 1H), 7.98 (d, J¼8.3 Hz, 2H), 7.37 (d,
332.0956.
J¼8.3 Hz, 2H), 7.18 (t, J¼7.9 Hz, 1H), 6.87e6.83 (m, 2H), 6.71 (dd,
J¼2.0, 8.2 Hz, 1H), 5.16 (s, 2H), 2.44 (s, 6H); 13C NMR (75 MHz,
4.4.2. N-(6-(Benzyloxy)-3-methylene-2,3-dihydrobenzofuran-2-yl)-
CDCl3)
d
158.4, 147.6, 144.0, 140.4, 133.0, 130.6, 129.9, 128.9, 122.7,
4-methylbenzenesulfonamide (2d). White solid (28 mg, 0.07 mmol,
119.7, 113.0, 111.1, 61.6, 21.9, 15.7; IR (KBr)
1574, 1476, 1395, 1228, 1195, 1178, 1091 cmꢂ1; HRMS (EI) calcd for
17H17O3N3S2 [M]þ 375.0711, found 375.0711.
n
3146, 3091, 3065, 1592,
60%); mp 99e102 ꢀC; 1H NMR (300 MHz, CDCl3)
d
7.86 (d, J¼8.1 Hz,
2H), 7.40e7.30 (m, 7H), 7.23 (d, J¼8.4 Hz, 1H), 6.53 (dd, J¼8.4,
2.1 Hz, 1H), 6.34 (dt, J¼10.5, 2.1 Hz, 1H), 6.31 (d, J¼2.1 Hz, 1H), 5.44
(d, J¼10.5 Hz, 1H), 5.41 (d, J¼2.4 Hz, 1H), 5.10 (d, J¼1.8 Hz, 1H), 4.99
C
4.3.13. N,N-Dimethyl-3-((1-tosyl-1H-1,2,3-triazol-4-yl)methoxy)ani-
(s, 3H), 2.45 (s, 3H); 13C NMR (75 MHz, CDCl3)
d 162.1, 162.0, 144.0,
line (1m). White solid (330 mg, 0.887 mmol, 78%); mp 132e134 ꢀC;
143.0, 138.4, 136.6, 129.8, 128.8, 128.3, 127.6, 127.5, 121.9, 116.8,
1H NMR (300 MHz, CDCl3)
d
8.19 (s, 1H), 7.98 (d, J¼8.4 Hz, 2H), 7.37
109.2, 103.8, 97.4, 89.5, 70.5, 21.8; IR (KBr) n 3274, 2927, 1620,
(d, J¼8.4 Hz, 2H), 7.13 (t, J¼8.5 Hz,1H), 6.41e6.37 (m,1H), 6.34e6.30
1596 cmꢂ1; HRMS (MALDI) calcd for C23H21NO4SNa [MþNa]þ
(m, 2H), 5.18 (s, 2H), 2.92 (s, 6H), 2.44 (S, 3H); 13C NMR (75 MHz,
340.1084, found 340.1080.
CDCl3)
d 159.2, 152.1, 147.5, 144.6, 133.0, 130.6, 130.0, 128.8, 122.6,
106.5, 102.0, 99.8, 61.6, 40.6, 21.9; IR (KBr)
n
3147, 3091, 1613, 1574,
4.4.3. N-(4,6-Dimethoxy-3-methylene-2,3-dihydrobenzofuran-2-yl)-
1503,1450,1393,1299,1234,1195,1177,1151,1091,1011 cmꢂ1; HRMS
4-methylbenzenesulfonamide (2e). White solid (39 mg, 0.11 mmol,
(ESI) calcd for C18H21N4O3S [MþH]þ 373.1334, found 373.1325.
85%); mp 138e141 ꢀC; 1H NMR (300 MHz, CDCl3)
d 7.86 (d,
J¼8.1 Hz, 2H), 7.33 (d, J¼8.1 Hz, 2H), 6.31 (dt, J¼10.5, 2.4 Hz, 1H),
5.99 (d, J¼1.8 Hz, 1H), 5.89 (d, J¼1.8 Hz, 1H), 5.65 (d, J¼2.4 Hz,
1H), 5.34 (d, J¼10.5 Hz, 1H), 5.09 (d, J¼2.4 Hz, 1H), 3.83 (s, 3H),
4.3.14. 4-((Naphthalen-1-yloxy)methyl)-1-tosyl-1H-1,2,3-triazole
(1n). White solid (1.04 g, 2.74 mmol, 83%); mp 121e123 ꢀC; 1H
NMR (300 MHz, CDCl3)
d
8.27 (s, 1H), 8.25e8.18 (m, 1H), 8.02 (d,
3.74 (s, 3H), 2.45 (s, 3H); 13C NMR (75 MHz, CDCl3)
d 163.8,
J¼8.5 Hz, 2H), 7.85e7.78 (m, 1H), 7.55e7.44 (m, 3H), 7.43e7.33 (m,
162.9, 157.6, 143.9, 141.5, 138.5, 129.8, 127.5, 105.9, 105.2, 92.2,
3H), 6.91 (d, J¼7.5 Hz, 1H), 5.39 (s, 2H), 2.46 (s, 3H); 13C NMR
89.7, 88.6, 55.8, 55.6, 21.8; IR (KBr)
n 3266, 2944, 1622,
(75 MHz, CDCl3)
d
153.9, 147.7, 144.5, 134.8, 133.2, 130.7,129.0,127.8,
1594 cmꢂ1
;
HRMS (ESI) calcd for C18H19NO5SNa [MþNa]þ
126.8, 125.9, 125.7, 122.6, 122.0, 121.5, 105.5, 62.2, 22.1; IR (KBr)
n
384.0882, found 384.0880.
3427, 1926, 1595 cmꢂ1; HRMS (MALDI) calcd for C20H18N3O3S
[MþH]þ 380.1063, found 380.1064.
4.4.4. 4-Methyl-N-(4,5,6-trimethoxy-3-methylene-2,3-
dihydrobenzofuran-2-yl)benzenesulfonamide
(28 mg, 0.07 mmol, 59%); mp 141e144 ꢀC; 1H NMR (300 MHz,
CDCl3)
(2f). White
solid
4.3.15. 4-((Naphthalen-2-yloxy)methyl)-1-tosyl-1H-1,2,3-triazole
(1o). White solid (941 mg, 2.48 mmol, 75%); mp 118e123 ꢀC; 1H
d
7.86 (d, J¼8.1 Hz, 2H), 7.34 (d, J¼8.1 Hz, 2H), 6.28 (dt,
NMR (300 MHz, CDCl3)
d
8.23 (s, 1H), 7.99 (d, J¼8.3 Hz, 2H),
J¼10.5, 2.4 Hz, 1H), 6.05 (s, 1H), 5.70 (d, J¼2.4 Hz, 1H), 5.36 (d,
7.83e7.69 (m, 3H), 7.45 (t, J¼7.5 Hz, 1H), 7.41e7.32 (m, 3H), 7.21
(d, J¼1.8 Hz, 1H), 7.17 (dd, J¼8.9, 2.5 Hz, 1H), 5.31 (s, 2H), 2.44 (s,
J¼10.5 Hz, 1H), 5.14 (d, J¼2.1 Hz, 1H), 3.96 (s, 3H), 3.79 (s, 3H),
3.76 (s, 3H), 2.46 (s, 3H); 13C NMR (75 MHz, CDCl3)
d 157.4, 156.6,
3H); 13C NMR (75 MHz, CDCl3)
d
156.0, 147.7, 144.3, 134.5, 133.1,
150.0, 143.9, 141.9, 138.5, 136.4, 129.8, 127.5, 108.4, 106.7, 90.6,
130.7, 129.9, 129.5, 129.0, 127.9, 127.1, 126.8, 124.3, 122.8, 118.8,
89.5, 61.5, 60.4, 56.4, 21.8; IR (KBr) n ;
2937, 1613, 1477 cmꢂ1
107.5, 61.8, 22.0; IR (KBr)
n
2127, 1629, 1391 cmꢂ1; HRMS
HRMS (APCI) calcd for C19H22NO6S [MþH]þ 392.1168, found
(MALDI) calcd for C20H18N3O3S [MþH]þ: 380.1063, found:
392.1172.
380.1078.
4.4.5. 4-Methyl-N-(7-methylene-6,7-dihydro-[1,3]dioxolo[4,5-f]ben-
zofuran-6-yl)benzenesulfonamide (2g). White solid (53 mg,
0.15 mmol, 95%); mp 156e158 ꢀC; 1H NMR (300 MHz, CDCl3)
4.4. Representative procedure for the synthesis of 3-
methylene-2,3-dihydrobenzofuran derivatives 2 (2a, 2de2g,
2k, 2ne2o)
d
7.85 (d, J¼8.2 Hz, 2H), 7.33 (d, J¼8.2 Hz, 2H), 6.73 (s, 1H), 6.32
(dt, J¼10.4, 2.4 Hz, 1H), 6.22 (s, 1H), 5.90 (d, J¼1.7 Hz, 2H),
5.40 (d, J¼10.4 Hz, 1H), 5.34 (d, J¼2.4 Hz, 1H), 5.07 (d, J¼2.4 Hz,
The procedure for the preparation of compound 2a is repre-
sentative for 2de2g, 2k and 2ne2o. To a stirred solution of 4-((3-
methoxyphenoxy)methyl)-1-tosyl-1H-1,2,3-triazole (1a) (100 mg,
0.278 mmol) in 1,2-dichloroethane (14 mL) was added rhodium (II)
octanoate dimer (11 mg; 0.014 mmol) under nitrogen atmosphere
and the resultant mixture was stirred at rt for 12 h. The reaction
mixture was diluted with dichloromethane (10 mL) and filtered
through a Celite pad. The Celite pad was washed with dichloro-
methane (20 mL) and the combined filtrate was evaporated to af-
ford the crude compound, which was purified by silica gel column
chromatography using 65% dichloromethane in hexane as a solvent
system to afford the desired product.
1H), 2.45 (s, 3H); 13C NMR (75 MHz, CDCl3)
d 156.5, 150.6,
144.1, 143.9, 143.1, 138.4, 129.9, 127.5, 115.8, 102.9, 101.8, 100.5,
93.7, 89.6, 21.8; IR (KBr)
n ;
3273, 2902, 1447, 1342, 1161 cmꢂ1
HRMS (ESI) calcd for C17H16NO5S [MþH]þ 346.0744, found
346.07433.
4.4.6. 4-Methyl-N-(6-methyl-3-methylene-2,3-dihydrobenzofuran-
2-yl)benzenesulfonamide (2j), 4-methyl-N-(4-methyl-3-methylene-
2,3-dihydro-benzofuran-2-yl)benzenesulfonamide
(2j0). Mixture
(2j:2j0¼4:1 by 1H NMR). Pale yellow solid (61 mg, 0.19 mmol,
66%); 2j 1H NMR (300 MHz, CH3OD)
d
7.83 (d, J¼8.2 Hz, 2H), 7.39
(d, J¼8.2 Hz, 2H), 7.28 (d, J¼7.8 Hz, 1H), 6.71 (d, J¼7.8 Hz, 1H),
6.44 (s, 1H), 6.32e6.21 (m, 1H), 5.55 (d, J¼2.4 Hz, 1H), 5.08 (d,
J¼2.4 Hz, 1H), 2.46 (s, 3H), 2.25 (s, 3H); 13C NMR (75 MHz,
4.4.1. N-(6-Methoxy-3-methylene-2,3-dihydrobenzofuran-2-yl)-4-
methylbenzenesulfonamide (2a). White solid (58 mg, 0.18 mmol,