Cu‑ACP‑Am‑Fe O @SiO : an efcient and recyclable heterogeneous catalyst ꢀor the…
3
4
2
Table 3 Comparison oꢀ catalytic activity oꢀ the Cu-ACP-Am-Fe O @SiO catalyst with literature precedents using Cu-based homogeneous and
3
4
2
heterogeneous catalysts ꢀor Chan–Lam coupling
Sr. no.
1
Catalyst
Base
Temp
60 °C
Solvent
DMF
Time
2 h
Yield/%
96
Reꢀerences
Cu-ACP-Am-Fe O @SiO
Et N
Present work
3
4
2
3
(0.018 mol% oꢀ Cu)
2
3
4
5
6
7
8
9
Cu(OAc) (2.0 equiv)
Et N/Pyridine
r.t.
r.t.
CH Cl
3 days
4–10 days
2 h
24 h
12 h
24 h
24 h
24 h
3 h
58
85
95
26–96
0–96
48–99
94
57–98
92
[21]
[22]
[23]
[24]
[25]
[26]
[27]
[28]
[29]
2
3
2
2
2
Cu(OAc) (2.5 equiv)
i-Pr NEt
CH Cl
2
2
2
Fe O –EDTA–Cu(II) (5 mol%)
–
50 °C
MW, 100 °C
r.t
r.t.
r.t.
50 °C
80 °C
H O
3
4
2
Cu(OAc) (2.0 equiv)
DBU
DMSO
CH Cl
2
Cu(OAc) (2.0 equiv)
Et N-Pyridine (1:2)
2
3
2
2
Cu(NO ) (2.0 equiv)
TMEDA
–
CH OH
3
2
3
CuCl (10 mol%)
CH OH
3
Cu(OAc) (2.0 equiv)
Et N
C H Cl
2
3
2
4
2
1
0
Cu–Fe O –TiO -L-dopa
K CO
H O
3
4
2
2
3
2
(
1.9 equiv)
1
1
CoFe O @SiO –NH -ꢀurꢀural-
Et N
r.t.
CH OH
5 h
94
[30]
2
4
2
2
3
3
Cu(OAc) (5 wt%)
2
1
1
2
3
Cu (Bdc) (Bpy)-Moꢀ (20 mg)
Cu@PI-COF (20 mg)
K CO
–
r.t.
r.t.
CH OH/H O
Methanol/water
1 h
8 h
85
91
[31]
[32]
2
2
2
3
3
2
condition. Moreover, the reaction proceeds at moderate tem-
perature which avoids the necessity oꢀ harsh temperature ꢀor
the Chan–Lam cross-coupling. The resultant heterogeneous
catalytic system exhibits remarkable efciency in terms oꢀ
product yield and high TON.
pressure and the product was puriꢂed by silica gel column
chromatography.
Acknowledgements One oꢀ the authors, DMP, is grateꢀul to acknowl-
edge Shivaji University, Kolhapur ꢀor ꢂnancial assistance through
Research Strengthening Scheme [SU/C&U.D.Section/89/1386].
Experimental
References
All commercial reagents boronic acid, amine, base, and sol-
vents were used without additional puriꢂcation. Analytical
thin-layer chromatography (TLC) was perꢀormed on Merck
precoated silica gel 60 F254 plates. Column chromatogra-
phy was perꢀormed with silica gel (60–120 mesh). Inꢀrared
spectra were recorded on Bruker FT-IR spectrophotometer.
NMR spectra were recorded on Bruker FT AM 400 MHz
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3
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1
0. Vantourout JC, Miras HN, Isidro-Llobet A, Sproules S, Watson
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3
In a 50 cm round-bottom ꢀlask, phenylboronic acid
(
(
1.2 mmol), primary amine (1.0 mmol), triethyl amine
11. Baruah J, Gogoi K, Dewan A, Borah G, Bora U (2017) Bull
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2.0 mmol), and 80 mg (0.018 mol% oꢀ Cu) Cu-ACP-Am-
3
12. Li B, Li M, Yao C, Shi Y, Ye D, Wu J, Zhao D (2013) J Mater
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Fe O @SiO were mixed in 5 cm DMF and the reaction
3
4
2
was allowed to stir at 60 °C temperature ꢀor 2 h in aerobic
condition. Reactions was monitored by thin-layer chroma-
tography (TLC) using aluminum-backed silica gel 60 (F254)
plates. Aꢀter completion oꢀ the reaction, the catalyst was
separated magnetically using bar magnet. Finally, the result-
ing solution was extracted with ethyl acetate and dried over
anhydrous Na SO . The solvent was removed under reduced
1
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