Nano copper oxide catalyzed synthesis of symmetrical diaryl selenides via cascade reaction of KSeCN with aryl halides

Article abstract of DOI:10.1055/s-0030-1260553

An unprecedented transfer of selenium ion from potassium selenocyanate was observed in C-Se cross-coupling reaction catalyzed by copper oxide nanoparticles under ligand-free conditions. Utilizing this protocol wide range of symmetrical diaryl selenides were obtained in excellent yields. Nano-CuO is recyclable up to four cycles without loss of catalytic activity. Georg Thieme Verlag Stuttgart · New York.

Full text of DOI:10.1055/s-0030-1260553

Accounts and
Rapid Communications in
Synthetic Organic Chemistry
SYNLETT
SUPPORTING INFORMATION
Supporting Information
for DOI: 10.1055/s-0030-1260553
© Georg Thieme Verlag KG Stuttgart · New York 2011
Thieme

Nano Copper Oxide Catalyzed Synthesis of Symmetrical Diaryl
Selenides via Cascade Reaction of KSeCN with Aryl Halides
K. Harsha Vardhan Reddy, V. Prakash Reddy, B. Madhav, J. Shankar, Y. V. D.
Nageswar*
Organic Chemistry Divison-I, Indian Institute of Chemical Technology, Hyderabad-500 607, India
dryvdnageswar@gmail .com
Contents:
General Information............................................................................................S2
General Procedure for the synthesis of symmetrical diaryl selenides ...........S3
Spectroscopic Data…………...............................................................................S4
Reference………………………………………………..………………………S7
Copies of 1H NMR and 13C NMR of Compounds..........................…………. .S8
S1

General Information:
CuO nano particles (mean particle size, 33 nm, surface area, 29 m2/g and purity, 99.99%)
were purchased from Sigma Aldrich. Analytical thin layer chromatography (TLC) was
carried out using silica gel 60 F254 pre-coated plates. Visualization was accomplished
with UV lamp or I2 stain. All products were characterized by their NMR and MS spectra.
13
1H and C NMR was recorded on 100, 200 and 300 MHz, in CDCl3 using TMS as the
internal standard, Chemical shifts were reported in parts per million (ppm, δ) downfield
from tetramethylsilane.
General procedure for synthesis of symmetrical diaryl selenides:
To a stirred solution of aryl halides (2.0 mmol) and potassium selenocyanate (1.2 equiv)
in dry DMSO (2.0 mL) at rt was added nano CuO (5.0 mol %) followed by KOH (2.0
0
equiv) and heated at 110 C for 15 h. The progress of the reaction was monitored by
TLC. After the reaction was complete, the reaction mixture was allowed to cool, and a
1:1 mixture of ethyl acetate/water (20 mL) was added. The combined organic extracts
were washed with brain and water and dried with anhydrous Na2SO4. The solvent and
volatiles were completely removed under vacuum to give the crude product, which was
purified by column chromatography on silica gel (petroleum ether/ethyl acetate) to afford
the corresponding coupling product in excellent yields.
Recycling of the catalyst:
After the reaction was complete, the reaction mixture was allowed to cool, and a 1:1
mixture of ethyl acetate/water (2.0 mL) was added and CuO was removed by
centrifugation. After each cycle, the catalyst was recovered by simple centrifugation,
washing with deionized water and ethyl acetate and then drying in vacuo. The recovered
nano-CuO was used directly in the next cycle.
S2

Demonstration of heterogeneous catalysis
To a stirred solution of iodo benzene (2.0 mmol) and potassium selenocyanate (1.0
mmol) in dry DMSO (2.0 mL) at rt was added CuO nanoparticles (5.0 mol %)
followed by KOH (2.0equiv) and heated at 110 0C for 15 h. The reaction mixture was
allowed to cool and the catalyst was separated via centrifugation and 0.5 mL of the
1
reaction mixture was worked out. The H NMR spectrum of the reaction mass
indicated 50% of product formation. This filtrate obtained after the catalyst separation
0
was further stirred for 7 h at 110 C and the reaction mixture was worked out. No
1
further progress of the reaction was observed as seen by H NMR spectroscopy and
the product remained at 50% only. This experiment clearly demonstrated that no
leaching of the catalyst is taking place and that the reaction is heterogeneous.
Powder X-ray diffraction analysis :
*
*
a Fresh nano copper
b Spent nano copper
*
*
*
*
*
*
*
b
a
10
20
30
40
50
60
70
80
2 Theta (deg.)
CuO remains CuO under the reaction conditions. This was confirmed by the powder X-
ray diffraction analysis exhibited identical peaks for both the fresh and recovered CuO
nanoparticles. It is observed that the shape and size of the particles remain unchanged and
supports the assumption that the morphology of the catalyst remains the same even after
recycling.
S3

Spectroscopic Data:
diphenylselane (Table 2, entry 1)1
1H NMR (CDCl3, 200 MHz): δ = 7.40-7.38 (m, 4H), 7.20-7.18 (m, 6H); 13C NMR
(CDCl3, 50 MHz): δ = 132.6, 131.1, 129.5, 127.7; Mass (ESI): m/z 251 [M+18].
Se
dip-tolylselane (Table 2, entry 4):2
1H NMR (200 MHz, CDCl3, TMS): δ = 7.28 (d, 4H, J = 8.12 Hz), 7.01 (d, 4H, J = 8.12
13
Hz), 2.31 (s, 6H); C NMR (CDCl3, 50 MHz): δ = 136.5, 132.83, 131.6, 129.4, 21.19;
Mass (ESI): m/z 263 [M+1].
Se
bis (4-ethylphenyl) selane (Table 2, entry 6):2
1H-NMR (200 MHz, CDCl3, TMS): δ = 7.34 (d, 4H, J = 8.12 Hz), 7.06 (d, 4H, J = 8.12
13
Hz), 2.59 (q, 4H, J = 7.54 Hz), 1.22 (t, 6H, J = 7.54 Hz). C-NMR (50 MHz, CDCl3,
TMS): δ =133.5, 132.8 128.4, 127.7, 28.2, 15.7. Mass (ESI): m/z 291 [M+1].
Se
MeO
OMe
bis(4-methoxyphenyl) selane(Table 2, entry 7):1
Yellow solid; 1H NMR (200 MHz, CDCl3, TMS): δ = 7.38 (d, 4H, J = 8.30 Hz), 6.75 (d,
4H, J = 8.30 Hz), 3.74 (s, 6H); 13C-NMR (50 MHz, CDCl3, TMS): δ = 159.2, 132.6,
114.8, 114.6, 55.4; Mass (ESI): m/z 295 [M+1].
S4

O2N
Se
NO2
bis (3-nitrophenyl)selane (Table 2, entry 9):2
Yellow solid; m. p.: 92-94 0C; 1H NMR (200 MHz, CDCl3, TMS): δ = 8.33 (s, 2H), 8.22-
13
8.16 (m, 2H), 7.77-7.74 (m, 2H), 7.50 (t, 2H, J = 7.55 Hz); C NMR (50 MHz, CDCl3,
TMS): δ = 148.6, 138.8, 131.7, 130.4, 127.7, 123.0; Mass (ESI): m/z 325 [M+1].
bis(3-fluorophenyl)selane (Table 2, entry 10):
1
Colorless oil; H NMR (200 MHz, CDCl3, TMS): δ = 7.32-7.12 (m, 6H), 7.02-6.93 (m,
2H); 13C NMR (50 MHz, CDCl3, TMS): δ = 164.6, 161.2, 130.6, 128.6, 119.9, 114.7
Mass (ESI): m/z 271 [M+1]. Anal calcd for: C12H8F2Se (269) C, 53.55; H, 3.00; Found:
C, 53.49; H, 2.92%.
dinaphthalen-1-ylselane (Table 2, entry 11):
yello liquid; IR (Neat): ν 3091, 2928, 1588, 1390, 1077, 968, 848 cm-1; 1H-NMR (200
MHz, CDCl3, TMS): δ = 8.05- 8.02 (m, 4H), 7.79- 7.65 (m, 4H), 7.55- 7.40 (m, 4H), 7.15
13
(t, 2H, J = 7.93Hz); C NMR (50 MHz, CDCl3, TMS): δ = 137.2, 133.9, 131.9, 128.8,
128.3, 127.5, 126.6, 125.6; Mass (ESI): m/z 335[M+1]; Anal calcd for: C20H14Se (334)
C, 72.07; H, 4.23%; Found: C, 72.01; H, 4.18%.
S5

bis(4-(benzyloxy)phenyl)selane (Table 2, entry 13):
1
Colorless oil; IR (Neat): ν 3099, 2923, 1598, 1397, 1081, 961, 842 cm-1; H-NMR (200
MHz, CDCl3, TMS): δ = 7.51 (d, 4H, J = 9.16 Hz), 7.39- 7.25 (m, 10H), 6.70 (d, 4H, J =
13
9.16 Hz), 5.02 (s, 4H); C NMR (50 MHz, CDCl3, TMS): δ = 158.63, 138.35, 136.35,
128.52, 128.11, 127.30, 117.53, 69.87; Mass (ESI): m/z 447 [M+1]; Anal calcd for:
C26H22O2Se (446) C, 70.11; H, 4.98%; Found: C, 70.04; H, 4.91%.
bis(3-(trifluoromethyl)phenyl)selane(Table 2, entry 14):
1
Colorless oil; IR (Neat): ν 3099, 2926, 1580, 1446, 1067, 858, 740 cm-1; H-NMR (200
MHz, CDCl3, TMS): δ = 7.87- 7.69(m, 2H), 7.62-7.15(m, 6H); 13C NMR (50 MHz,
CDCl3, TMS): δ = 136.24, 134.86, 129.86, 129.55, 128.27, 124.63; Mass (ESI): m/z 371
[M+1]; Anal calcd for C14H8F6Se (370) C, 45.55; H, 2.18%; Found: C, 45.48; H,
2.13%.
Dithiophen-3-ylselane (Table 2, entry 15):2
1
Colorless oil; H-NMR (200 MHz, CDCl3, TMS): δ = 7.32-7.21 (m, 4H), 7.07-6.96 (m,
2H); 13C NMR (50 MHz, CDCl3, TMS): δ = 131.7, 126.8, 126.3, 123.7; Mass (ESI): m/z
247 [M+1]; Anal calcd for C8H6S2Se(246) C, 39.18; H, 2.47; S, 26.15%; Found: C,
39.29; H, 2.51%.
Dithiophen-2-ylselane (Table 2, entry 16):2
1
Colorless oil; H-NMR (200 MHz, CDCl3, TMS): δ = 7.30-7.28 (m, 2H), 7.21-7.19 (m,
2H), 6.87 (dd, 2H, J = 3.58 Hz); 13C NMR (50 MHz, CDCl3, TMS): δ = 134.9, 131.1,
S6

127.5, 126.2; Mass (ESI): m/z247 [M+1]; Anal calcd for C8H6S2Se(246) C, 39.18; H,
2.47; S, 26.15%; Found: C, 39.26; H, 2.53%.
Dipyridin-3-ylselane (Table 2, entry 18):2
1H-NMR (200 MHz, CDCl3): δ = 8.69 (s, 2H), 8.58-8.52 (m, 2H), 7.73 (d, 2H, J = 7.93
Hz), 7.25-7.19 (m, 2H); 13C NMR (50 MHz, CDCl3, TMS): δ = 153.3, 148.9, 140.6,
124.4; Mass (ESI): m/z 237 [M+1]; Anal calcd for: C10H8N2Se (236) C, 51.08; H, 3.43;
N, 11.91; C, 51.14; H, 3.46; N, 11.95.
dipyrimidin-5-ylselane (Table 2, entry 20):
1
Colorless oil;IR (neat): ν 3092, 2960, 1597, 1444, 1068, 865, 738 cm-1; H-NMR (200
13
MHz, CDCl3, TMS): δ = 7.51(s, 2H), 7.25(s, 4H); C NMR (50 MHz, CDCl3, TMS): δ
= 132.9, 129.0, 127.5; Mass (ESI): m/z 239 [M+1]; Anal calcd for: C8H6N4Se (238) C,
40.52; H, 2.55; N, 23.63%; Found: C, 40.46; H, 2.45; N, 23.57%.
Dipyrazin-2-ylselane (Table 2, entry 21):2
White solid; m. p.: 96-98 0C;IR (KBr): 3028, 2923, 1556, 1452, 1042, 833, 738 cm-1; 1H-
13
NMR (200 MHz, CDCl3, TMS): δ = 8.75 (s, 2H), 8.45-8.42 (m, 4H); C NMR (50
MHz, CDCl3, TMS): δ = 148.1, 145.1, 142.7; Mass (ESI): m/z 239 [M+1]; Anal calcd
for: C8H6N4Se (238) C, 40.52; H, 2.55; N, 23.63%; Found: C, 40.45; H, 2.48; N,
23.59%.
References: (1) Alves, D.; Santos, C. G.; Paixao, M. W.; Soares, L. C.; de
Souza, D.; Rodrigues, O. E. D.; Braga, A. L. Tetrahedron Lett. 2009, 50, 6635.
(2) Reddy, V. P.; K.; Kumar, A. V.; Rao, K. R. J. Org. Chem. 2010, 75, 8720.
S7

Copies of 1H NMR and 13C NMR of Compounds:
diphenylselane (Table 2, entry 1)
Se
7.5
7.0
6.5
6.0
5.5
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0.0
140
130
120
110
100
90
80
70
60
50
40
30
20
10
0
S8

dip-tolylselane (Table 2, entry 4):
Se
7.5 7.0 6.5 6.0 5.5 5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0.0
140
130
120
110
100
90
80
70
60
50
40
30
20
10
0
S9

bis (4-ethylphenyl)selane (Table 2, entry 6):
Se
7.5
7.0
6.5
6.0
5.5
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0.0
140
130
120
110
100
90
80
70
60
50
40
30
20
10
0
S10

bis(4-methoxyphenyl) selane(Table 2, entry 7):
Se
MeO
OMe
8.0
7.5
7.0
6.5
6.0
5.5
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0.0 -0.5
160
150
140
130
120
110
100
90
80
70
60
50
40
30
20
10
0
S11

bis (3-nitrophenyl)selane (Table 2, entry 9):
O2N
Se
NO2
8.5
8.0
7.5
7.0
6.5
6.0
5.5
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0.0
150
140
130
120
110
100
90
80
70
60
50
40
30
20
10
0
S12

bis(3-fluorophenyl)selane (Table 2, entry 10):
F
Se
F
7.5
7.0
6.5
6.0
5.5
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0.0
160
150
140
130
120
110
100
90
80
70
60
50
40
30
20
10
0
S13

dinaphthalen-1-ylselane (Table 2, entry 11):
Se
8.0
7.5
7.0
6.5
6.0
5.5
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0.0
140
130
120
110
100
90
80
70
60
50
40
30
20
10
0
bis(4-(benzyloxy)phenyl)selane (Table 2, entry 13):
Se
O
O
7.5
7.0
6.5
6.0
5.5
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
S14

160
150
140
130
120
110
100
90
80
70
60
50
40
30
20
10
0
-10
bis(3-(trifluoromethyl)phenyl)selane(Table 2, entry 14):
F3C
Se
CF3
8.0
7.5
7.0
6.5
6.0
5.5
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0.0
150
140
130
120
110
100
90
80
70
60
50
40
30
20
10
0
-10
S15

Dithiophen-3-ylselane (Table 2, entry 15):
Se
S
S
7.5
7.0
6.5
6.0
5.5
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0.0
150
140
130
120
110
100
90
80
70
60
50
40
30
20
10
0
Dithiophen-2-ylselane (Table 2, entry 16):
S
S
S
7.5
7.0
6.5
6.0
5.5
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0.0
S16

140
130
120
110
100
90
80
70
60
50
40
30
20
10
0
Dipyridin-3-ylselane (Table 2, entry 18):
Se
N
N
9.0
8.5
8.0
7.5
7.0
6.5
6.0
5.5
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0.0
150
140
130
120
110
100
90
80
70
60
50
40
30
20
10
0
S17

dipyrimidin-5-ylselane (Table 2, entry 20):
Se
N
N
N
N
7.5
7.0
6.5
6.0
5.5
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0.0
130
120
110
100
90
80
70
60
50
40
30
20
10
0
Dipyrazin-2-ylselane (Table 2, entry 21):
N
Se
N
N
N
9.0 8.5 8.0 7.5 7.0 6.5 6.0 5.5 5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0.0
S18

150
140
130
120
110
100
90
80
70
60
50
40
30
20
10
0
S19