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Preparation of
Cu-SILC
Mercaptopropyl silica gel (powder for column chromatography
supplied by Fuji Silysia Chemical LTD., 2.068 g) and CuBr˙Me2S
(62 mg, 0.302 mmol) were added to a solution of [bmim]PF6 (200
mg, 10 wt%) in MeCN. Resulting slurry was stirred at r.t.
for 4 h, when the brown color of MeCN solution was transparent.
After evaporation of MeCN in vacuo, the powder was rinsed with anhyd
Et2O (5×). Evacuation of in vacuo provided Cu-SILC
(2.301 g, 0.15 mmol/g SiO2) as white powder.
21
Click Reaction
of Benzylazide and 2-Methylbut-3-yn-2-ol
A suspension
of benzylazide (65 mg, 0.49 mmol), 2-methyl-but-3-yn-2-ol (51 mg,
0.61 mmol), and Cu-SILC (299 mg, 0.035 mmol CuBr) in 50% aq
EtOH (2 mL) was stirred at r.t. for 2 h. The organic layer was separated
by filtration and the flask was rinsed with Et2O. The
combined organic layer was evaporated to dryness in vacuo. The residue
was purified by column chromatography (eluent: n-hexane-EtOAc = 3:1
to 1:5) to afford 2-[1-benzyl-1,2,3-triazol-4-yl]propan-2-ol (3a, 96 mg, 91%). Recovered Cu-SILC
was used intact for further recycle experiments.
22 Compound 3d: ¹H
NMR (270 MHz, CDCl3): δ = 2.11-2.22 (m,
2 H), 2.38 (br s, 1 H), 2.67-2.88 (m, 2 H), 4.88 (br s,
1 H), 5.51 (s, 2 H), 7.14-7.40 (m, 11 H). ¹³C
NMR (67.5 MHz, CDCl3): δ = 151.5,
141.4, 134.4, 129.0, 128.7, 128.4, 128.3, 128.0, 125.8, 120.1, 66.4,
54.2, 38.9, 31.7. IR: 3409, 3011, 1496, 1456, 1224, 1049 cm-¹.
HRMS: m/z [M]+ calcd
for C18H19N3O: 293.1528; found:
293.1524.
23 Compound 3h: ¹H
NMR (270 MHz, CDCl3): δ = 1.64
(s, 6 H), 1.79 (s, 6 H), 2.24 (s, 10 H), 7.50 (s, 1 H). ¹³C
NMR (67.5 MHz, CDCl3): δ = 154.2,
115.2, 68.6, 59.5, 43.0, 36.0, 30.6, 30.5, 29.5. IR: 3398, 2981,
2857, 1454, 1360, 1310, 1167, 1057, 1026, 954, 854 cm-¹.
HRMS: m/z [M]+ calcd
for C15H23N3O: 261.1841; found:
261.1838.
24 Compound 3j: ¹H
NMR (270 MHz, CDCl3): δ = 0.03
(s, 6 H), 0.85 (s, 9 H), 1.23 (s, 3 H), 1.31 (s, 3 H), 1.57 (s,
3 H), 1.59 (s, 3 H), 3.61-3.79 (m, 3 H), 4.17-4.23
(m, 1 H), 4.41 (dd, J = 14.3,
5.9 Hz, 1 H), 4.63 (dd, J = 14.3,
3.2 Hz, 1 H), 7.57 (s, 1 H). ¹³C NMR
(67.5 MHz, CDCl3): δ = 155.3, 120.6,
109.7, 77.3, 77.1, 68.2, 62.9, 51.6, 30.4, 30.3, 26.9, 26.9, 25.9,
18.3, -5.4, -5.5. IR: 3450, 2988, 2956, 2931, 2110,
1463, 1383, 1255, 1089, 838 cm-¹. HRMS: m/z [M]+ calcd
for C18H35N3O4Si: 385.2397;
found: 385.2392.
25 Compound 3k: ¹H
NMR (270 MHz, CDCl3): δ = 1.30
(s, 3 H), 1.41 (s, 3 H), 1.64 (s, 3 H), 1.65 (s, 3 H), 2.12 (s,
3 H), 2.53 (br s, 1 H), 3.88-3.94 (m, 1 H), 4.12-4.25
(m, 3 H), 4.54 (dd, J = 14.4,
5.1 Hz, 1 H), 4.63 (dd, J = 14.4,
3.6 Hz, 1 H), 7.61 (s, 1 H). ¹³C NMR
(67.5 MHz, CDCl3): δ = 170.4, 155.6,
120.8, 110.3, 76.1, 75.5, 68.2, 63.2, 50.9, 30.4, 30.3, 26.9, 26.8,
20.7. IR: 3470, 2989, 1742, 1374, 1226, 1167, 1046 cm-¹.
HRMS: m/z [M]+ calcd
for C14H23N3O5: 313.1637;
found: 313.1638.
26 Compound 3l: ¹H
NMR (270 MHz, CDCl3): δ = 0.97
(d, J = 6.6
Hz, 3 H), 1.19-1.52 (m, 3 H), 1.59 (s, 3 H), 1.64 (s, 6
H), 1.68 (s, 3 H), 1.73-1.78 (m, 1 H), 1.88-2.00
(m, 3 H), 2.52 (br s, 1 H), 4.32-4.38 (m, 2 H), 5.04-5.09
(m, 1 H), 7.42 (s, 1 H). ¹³C NMR (67.5
MHz, CDCl3): δ = 155.4,
131.2, 123.9, 118.8, 68.1, 48.2, 37.1, 36.5, 30.3, 29.8, 25.5, 25.1, 19.0,
17.5. IR: 3408, 2976, 2929, 1460, 1380, 1168, 1052, 955, 853 cm-¹.
HRMS: m/z [M]+ calcd
for C15H27N3O: 265.2154; found:
265.2158.
