N-Fluorobenzenaminium tetrafluoroborate generated in situ by aniline and Selectfluor as a reusable catalyst for the ring opening of epoxides with amines under microwave irradiation

Article abstract of DOI:10.1039/c4cy00609g

The ring opening of epoxides with aromatic and aliphatic amines was carried out under solvent free conditions using N-fluorobenzenaminium tetrafluoroborate (2 mol%) generated in situ by the reaction of aniline and Selectfluor as a catalyst with microwave irradiation. Excellent yields of β-amino alcohols were obtained. The catalyst also results in the retention of the stereochemistry for the ring opening of enantiopure epoxide with amine. The catalyst was recovered and reused up to 4 cycles for the ring opening of cyclohexene oxide with aniline. This journal is

Full text of DOI:10.1039/c4cy00609g

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N-Fluorobenzenaminium tetrafluoroborate
generated in situ by aniline and Selectfluor as a
reusable catalyst for the ring opening of epoxides
with amines under microwave irradiation†
Cite this: Catal. Sci. Technol., 2014,
4, 3945
*
ManMohan Singh Chauhan, Geeta Devi Yadav, Firasat Hussain and Surendra Singh
The ring opening of epoxides with aromatic and aliphatic amines was carried out under solvent free
conditions using N-fluorobenzenaminium tetrafluoroborate (2 mol%) generated in situ by the reaction of
aniline and Selectfluor as a catalyst with microwave irradiation. Excellent yields of β-amino alcohols were
obtained. The catalyst also results in the retention of the stereochemistry for the ring opening of enantio-
pure epoxide with amine. The catalyst was recovered and reused up to 4 cycles for the ring opening of
cyclohexene oxide with aniline.
Received 9th May 2014,
Accepted 25th June 2014
DOI: 10.1039/c4cy00609g
www.rsc.org/catalysis
phosphonate,15 montmorillonite clay,16 silica,17 alumina/modi-
fied alumina,18 zeolites,19 Fe-MCM-41,20 heterodimetallic
Introduction
Selectfluor (1-chloromethyl-4-fluoro-1,4-diazoniabicyclo[2.2.2]
octane bis(tetrafluoroborate)) is a commercially available,
exceptionally stable and virtually nonhygroscopic crystalline
solid which is widely used for the electrophilic fluorination of
electron-rich carbon centers.1,2 Its electrophilic and oxidative
characteristics make it a useful catalyst for the cleavage of
electron-rich protecting groups, such as p-methoxybenzylidene
(PMP), tetrahydropyranyl (THP) ethers, 1,3-dithianes, the
deprotection of silyl ethers and the ring opening of epoxides
with ammonium thiocyanate (Scheme 1).3–5
The ring opening of epoxide with an amine as a nucleo-
phile is an important route for the synthesis of β-amino
alcohols.6 β-Amino alcohols are versatile intermediates for
the synthesis of a wide range of biologically active natural
and synthetic products, synthetic amino acids, β-blockers in
pharmaceuticals and insecticides.7 The cleavage of epoxides
with amines has been carried out in the presence of metal
halides,8 metal triflates,9 metal alkoxides,10 metal amides and
triflamide,11 transition metal salts,12 hexafluoro-2-propanol
under reflux (HFIP),13 ionic liquid,14 zirconium sulfophenyl
coordination polymers,21 poly(amidoamine) dendrimer
supported on cross-linked polystyrene,22 and N-formyl-L-proline,23
in water without catalyst24 and Fe(Cp)2BF4.25 A few research
groups have also reported the desymmetrisation of meso
epoxides with aniline derivatives using chiral complexes and
organocatalysts.26
Some of the existing methods still have limitations, for
example, less basic amines fail to open these epoxides under
ambient conditions, a high loading of expensive catalyst is
required, the catalysts used may be air and moisture sensi-
tive, non-environmentally friendly solvents are required and
reactions require long times to complete. Microwave irradia-
tion has become an increasingly popular method for acceler-
ating synthetic transformations.27 This technology offers a
clean, effective and convenient method for heating, which
often results in higher yields and shorter reaction times.
Organic reactions assisted by microwave irradiation have
recently attracted considerable attention.28 So far few exam-
ples have been reported in the literature for the ring opening
of epoxides with amines under microwave irradiation.29
Herein, we report N-fluorobenzenaminium tetrafluoroborate
Department of Chemistry, University of Delhi, Delhi-110007, India.
E-mail: ssingh1@chemistry.du.ac.in
† Electronic supplementary information (ESI) available: Crystal structure
analysis of (S)-1-(naphthalen-2-yloxy)-3-piperidin-1-yl-propan-2-ol hydrochloride
(20·HCl): C18H24NO2Cl, Mr = 321.83, monoclinic, space group: P21, a = 8.117(5),
b = 7.669(5), c = 28.305(5) Å, β = 95.859(5)°, V = 1755.6(16) Å3, ρcalcd. = 1.218 g cm−3
,
Z = 4, F(000) = 688, crystal dimensions: 0.46 × 0.18 × 0.09 mm. The refinement
converged at R1 = 0.0619, wR2 = 0.1098 for all data; final GOF: 1.003; largest
peak/hole in the final difference Fourier map: 0.27/–0.16 e Å−3 and absolute
structure parameter −0.07(6). CCDC 895046. For ESI and crystallographic data
in CIF or other electronic format see DOI: 10.1039/c4cy00609g
Scheme 1 In situ generation of catalyst N-fluorobenzenaminium
tetrafluoroborate (1).
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as a new catalyst in situ generated by the reaction of aniline
and Selectfluor for the ring opening of a variety of epoxides
with aliphatic and aromatic amines under solvent free condi-
tions with microwave irradiation.
Selectfluor and aniline and recording the 19F-NMR spectra . The
peak for the N–F bond in Selectfluor at +47.8 ppm disappeared
and a new peak at −129.6 ppm developed due to the formation
of the PhNH2F cation and a peak at −150.6 was present due to
the formation of the BF4 anion (Fig. 1). The byproduct of this
reaction, 1-(chloromethyl)-4-aza-1-azonia-bicyclo[2.2.2]octane
tetrafluoroborate (2), was confirmed by the presence in the
1H NMR spectrum of peaks at 3.23 (t, J = 8.0 Hz), 3.50 (t, J =
8.0 Hz) and 5.03 (s) ppm, the spectrum was identical to that
of the separately synthesized pure compound 2 (see ESI†). The
1H NMR spectra of in situ generated catalyst 1 and isolated
N-fluorobenzenaminium tetrafluoroborate (1) (see ESI†) are also
identical (Fig. 2). In the 13C NMR spectrum of in situ generated
catalyst 1, downfield shifting of 3 peaks (CH) and 1 peak upfield
(quartinary carbon) were observed compared to the peaks
present in the spectrum of aniline which shows that electro-
philic fluorination took place on the N-atom of aniline and
that the in situ generated catalyst 1 is N-fluorobenzenaminium
tetrafluoroborate (1) (Fig. 3). Furthermore, we also confirmed
that the actual catalyst is 1 by HRMS, that the peak at 112.0561 [M]+
Results and discussion
We conducted the ring opening of cyclohexene oxide 3 with
aniline and Selectfluor (10 mol%) with microwave irradiation
at 80 °C and 200 W for 10 min giving a 94% yield of the
product 6a (Table 1, entry 1). We were interested to find out
the mechanism for this reaction as well as the actual catalyst
for this reaction. Aniline is a nucleophile and Selectfluor is
an electrophilic reagent thus a fluorine atom could transfer to
the N-atom of aniline to form N-fluorobenzenaminium
tetrafluoroborate (1). The formation of N-fluorobenzenaminium
tetrafluoroborate (1) was confirmed by 19F-NMR, 1H-NMR and
13C-NMR spectroscopy. The electrophilic fluorination of amines
by Selectfluor has also been reported in the literature.30 The
first experiment was carried out by mixing a 1 : 1 molar ratio of
Table 1 Ring-opening of cyclic epoxides with different anilines using in situ generated N-fluorobenzenaminium tetrafluoroborate (1) and its derivatives
by aniline/substituted anilines and Selectfluor with microwave irradiationa
Entry
Epoxides
Catalyst loading (mol%)
Amine
Products
Temp. (°C)
Yieldb(%)
1
2
3
4
3
3
3
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
10
5
5
5
2
—
2
2
2
2
2
2
2
2
2
2
2
5a
5a
5a
5a
5a
3a
5a
5a
5a
5b
5c
5d
5e
5a
5b
5c
5d
5e
6a
6a
6a
6a
6a
6a
6a
6a
6a
6b
6c
6d
6e
7a
7b
7c
7d
7e
80
80
70
50
70
70
70
70
70
70
70
70
70
60
60
60
60
60
94
93
95
80
98
—
94
—
90
72
67
86
93
90
77
84
90
96
5
6c
7d
8e
9 f
10
11
12
13
14
15
16
17
18
2
a
Selectfluor (2–10 mol%) and aniline/substituted aniline (2–10 mol%), epoxides (2 mmol) and aniline/substituted aniline (2.0 mmol) were
b
irradiated under microwave irradiation @ 200 W at specified temperature for 10 min. Isolated yield after purification by column
chromatography. The reaction conducted in absence of Selectfluor under microwave irradiation. The reaction conducted with isolated
c
d
e
N-fluorobenzenaminium tetrafluoroborate (1) under microwave irradiation. The reaction conducted with isolated 1-(chloromethyl)-4-aza-1-
azonia-bicyclo[2.2.2]octane tetrafluoroborate (2) under microwave irradiation. f The reaction conducted on conventional oil bath heating for 1.5 h.
3946 | Catal. Sci. Technol., 2014, 4, 3945–3952
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Fig. 1 19F-NMR data, recorded in D2O solvent, for the isolated catalyst 1, in situ generated catalyst 1, 1-(chloromethyl)-4-aza-1-azonia-
bicyclo[2.2.2]octane tetrafluoroborate (2) and Selectfluor.
is due to N-fluorobenzenaminium cation and that the peak at
161.0847 is due to the byproduct of 1-(chloromethyl)-4-aza-1-
azonia-bicyclo[2.2.2]octane cation (2) and these are also iden-
tical to the peaks in the spectra of their pure isolated com-
pounds (see ESI,† Fig. S3–S5).
aniline were also investigated with microwave irradiation and
resulted in 77–96% yields of the products 7a–e (Table 1,
entries 14–18).
The ring opening of cyclohexene oxide (3) with primary
amines and secondary amines were carried out with micro-
wave irradiation at 70 °C for 10 min. The ring opening of
cyclohexene oxide (3) with piperidine in the absence of
N-fluorobenzenaminium tetrafluoroborate (1), gave 28%
conversion of the product (Table 2, entry 1). The use of
N-fluorobenzenaminium tetrafluoroborate (1) as a catalyst
improved the conversion up to 45% (Table 2, entry 2). We also
used morpholine, which gave 99% conversion of epoxide to
the product (Table 2, entry 3). Primary amines like benzyl
amine and (S)-α-methylbenzylamine gave 94–96% conversions
of the corresponding products (Table 2, entries 4 and 5).
The ring opening of a variety of epoxides with aniline was
carried out using in situ generated N-fluorobenzenaminium
tetrafluoroborate (1) as a catalyst under solvent free condi-
tions with microwave irradiation at 70 °C for 10 min. The
ring opening of 1,2-epoxy-5-cyclooctene (8) with aniline
afforded a 69% yield of the trans-β-amino alcohol 9. The ring
opening of terminal aliphatic epoxides (1,2-epoxyhexane 10
and 1,2-epoxydecane 12) with aniline occurred at the termi-
nal carbon of the epoxides, resulting in the major products
11a and 13a. Minor regioisomeric products 11b and 13b were
also obtained by nucleophilic attack of aniline at the second-
ary carbon of the epoxides. The regioisomeric ratio was deter-
mined by 1H NMR by integrating peaks at δ 3.72 and
We optimised the reaction conditions for the ring opening
of cyclohexene oxide (3) with aniline. The catalyst loading
was reduced by 5 mol% and the temperature was decreased
to 70 °C, which improved the yield (Table 1, entries 2 and 3).
Furthermore, the reaction temperature was decreased to
50 °C and comparative lower yield (80%) was obtained (Table 1,
entry 4). The catalyst loading (2 mol%) was sufficient to catal-
yse the reaction and afforded a 98% yield of the product 6a
(Table 1, entry 5). We were unable to obtain product 6a, in
the absence of catalyst and the unreacted substrates were
recovered (Table 1, entry 6). The isolated catalyst 1, also gave
a 94% yield of the product 6a but 1-(chloromethyl)-4-aza-1-
azonia-bicyclo[2.2.2]octane tetrafluoroborate (2) did not catal-
yse the reaction (Table 1, entries 7 and 8).
The ring opening of epoxide 3 with aniline at 70 °C with
conventional oil bath heating afforded 6a in 90% yield
after 1.5 h (Table 1, entry 9). The reaction of epoxide 3 with
2-methoxy, 2-methyl, 4-methoxy and 4-methyl aniline using
Selectfluor (2 mol%) with microwave irradiation, in situ
generated substituted N-fluorobenzenaminium tetrafluoroborate
as a catalyst and gave corresponding products 6b–e in 67–93%
yields. Furthermore, the ring opening of cyclopentene oxide
4 with aniline, 2-methoxy, 2-methyl, 4-methoxy and 4-methyl
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Fig. 2 1H-NMR data, recorded in D2O solvent, for the isolated catalyst 1, in situ generated catalyst 1, 1 : 1 mixed isolated catalyst 1 and
1-(chloromethyl)-4-aza-1-azonia-bicyclo[2.2.2]octane
tetrafluoroborate
(2),
1-(chloromethyl)-4-aza-1-azonia-bicyclo[2.2.2]octane
tetrafluoroborate (2) and Selectfluor.
We also tested the in situ generation of N-fluoro-
benzenaminium tetrafluoroborate (1) as a catalyst for the
ring opening of (S)-2-((naphthalen-1-yloxy)methyl)oxirane
(16)-S with morpholine and piperidine, this afforded excel-
lent yields of products 20 and 21 with retention of the stereo-
chemistry (Scheme 2). The enantiopure epoxide 16-(S) was
synthesized by the resolution of racemic epoxide 16 using
Jacobsen's HKR (hydrolytic kinetic resolution) with water,
affording a 45% yield.31 The naphthyloxy-β-amino alcohols
20 and 21 have been reported in the literature to have anti-
malarial activity.32 The absolute configuration of compound
20 was determined by single crystal X-ray diffraction by pre-
paring its hydrochloride salt and the absolute configuration
of 20·HCl salt was found to be (S) (see Fig. 4).
We also investigated whether the in situ generated
N-fluorobenzenaminium tetrafluoroborate (1) could be
recycled and reused for the next catalytic run. The ring open-
ing of cyclohexene oxide with aniline was carried out at
8 mmol using in situ generated N-fluorobenzenaminium
tetrafluoroborate (1) (2 mol%), to afford product 6a with 98%
Fig. 3 13C-NMR of in situ generated catalyst 1 and a mixture of aniline
and compound 2.
3.64 ppm corresponding to compounds 11a and 11b. The total
yield of both of the regioisomers (11a and 11b) was 88% with a
ratio of 77: 23 (Table 3, entry 2). The ring opening of epichloro-
hydrin with aniline resulted exclusively in β-amino alcohol 15
as a product. The ring opening of 2-((naphthalen-1-yloxy)
methyl)oxirane (16) with aniline gave an 82% yield of product
17 (Table 3, entry 5). The ring opening of styrene oxide resulted
in 2-anilino-2-phenyl ethanol (19) with 65% yield.
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Table 2 Ring-opening of cyclohexene oxide with different aliphatic
amines using in situ generated catalyst 1 as the catalyst with microwave
irradiationa
β-amino alcohols by the reaction of the cyclic epoxides with
aniline or substituted anilines. We have also synthesized
enantiopure naphthyloxy-β-amino alcohols, which has anti-
malarial activity. In addition, we have demonstrated that
in situ generated catalyst 1 could be recovered from the reac-
tion mixture and reused up to 4 cycles with a reasonably
good yield of product.
Entry
1
Amine
Product
Conversionb(%)
28c
Acknowledgements
S. S. acknowledges the financial assistance from the Univer-
sity of Delhi and the University Science Instrumentation
Center (USIC), University of Delhi, India for analytical data.
M. S. C. is thankful to UGC for providing SRF.
2
3
4
45
99
94
Notes and references
1 (a) R. E. Banks, M. K. Besheesh, S. N. Mohialdin and
I. Sharif, J. Chem. Soc., Perkin Trans. 1, 1996, 2069; (b)
P. T. Nyffeler, S. G. Duron, M. D. Burkart, S. P. Vincent and
C.-H. Wong, Angew. Chem., Int. Ed., 2005, 44, 192.
2 G. W. Bluck, N. B. Carter, S. C. Smith and M. D. Turnbull,
J. Fluorine Chem., 2004, 125, 1873.
3 J. Liu and C.-H. Wong, Tetrahedron Lett., 2002, 43, 4037.
4 S. T. A. Shah, S. Singh and P. J. Guiry, J. Org. Chem., 2009,
74, 2179.
5
96d
5 J. S. Yadav, B. V. S. Reddy and C. S. Reddy, Tetrahedron Lett.,
2004, 45, 1291.
6 (a) D. M. Hodgson, A. R. Gibbs and G. P. Lee, Tetrahedron,
1996, 52, 14361; (b) S. C. Bergmeier, Tetrahedron, 2000,
56, 2561.
a
The in situ generated catalyst 1 (2 mol%), cyclohexene oxide
(2 mmol) and amines (2.0 mmol) were microwave irradiated at
b
200 W and 70 °C for 10 min. Conversion of epoxide to product was
determined by gas chromatography.c The reaction was carried out in
7 (a) D. J. Ager, I. Prakash and D. R. Schaad, Chem. Rev., 1996,
96, 835; (b) E. J. Corey and F.-Y. Zhang, Angew. Chem., Int.
Ed., 1999, 38, 1931; (c) C. W. Johannes, M. S. Visser,
G. S. Weatherhead and A. H. Hoveyda, J. Am. Chem. Soc.,
1998, 120, 8340; (d) B. L. Chng and A. Ganesan, Bioorg. Med.
Chem. Lett., 1997, 7, 1511; (e) D. A. Alonso, D. Guijarro,
P. Pinho, O. Temme and P. G. Andersson, J. Org. Chem.,
1998, 63, 2749; ( f ) P. Castejon, A. Moyano, M. A. Pericas
and A. Riera, Tetrahedron, 1996, 52, 7063; (g) G. Li,
H.-T. Chang and K. B. Sharpless, Angew. Chem., Int. Ed.
Engl., 1996, 35, 451.
8 (a) CoCl2: J. Iqbal and A. Pandey, Tetrahedron Lett., 1990, 31,
575; (b) SmI2: P. Van de Weghe and J. Collin, Tetrahedron
Lett., 1995, 36, 1649; (c) SmCl3: X.-L. Fu and S.-H. Wu, Synth.
Commun., 1997, 27, 1677; (d) TaCl5: S. Chandrasekhar,
T. Ramchander and S. J. Prakash, Synthesis, 2000, 1817; (e)
CeCl3: L. R. Reddy, M. A. Reddy, N. Bhanumathi and
K. R. Rao, Synthesis, 2000, 831; ( f ) BiCl3: T. Ollevier and
G. Lavie-Compin, Tetrahedron Lett., 2002, 43, 7891; (g) BiCl3:
N. R. Swamy, G. Kandaji and G. Nagaiah, Synth. Commun.,
2002, 13, 2307; (h) (C4H12N2)2[BiCl6]Cl·H2O: H.-F. Lu,
L.-L. Sun, W.-J. Le, F.-F. Yang, J.-T. Zhou and Y.-H. Gao,
Tetrahedron Lett., 2012, 53, 4267; (i) ZnCl2: L. D. Pachón,
P. Gamez, J. J. M. Van Brussel and J. Reedijk, Tetrahedron
Lett., 2003, 44, 6025; ( j) VCl3: G. Sabitha, G. S. K. K. Reddy,
d
the absence of in situ generated catalyst 1. The diasteromeric ratio
was determined by gas chromatography and was found to be 1 : 0.94.
yield. The reaction mixture was diluted with diethyl ether
(1 mL) and then hexane (5 mL) was added and the resulting
mixture was stirred for 2 minutes, the solvent was then
decanted. The in situ generated catalyst 1 was separated out
as a viscous oil, which was dried under vacuum and reused
for the next catalytic run. The 1H and 19F NMR spectra of
recovered catalyst 1, were similar to those of the in situ gener-
ated catalyst 1 (see ESI,† Fig. S1–S2). The catalyst was reused
up to 4 cycles. The yields of the products were found to be in
the range of 95–86% for up to 3 cycles but in the 4th cycle we
obtained a 40% yield which may be due to the physical loss
of the catalyst (Table 4).
Conclusions
In conclusion, we investigated the catalysis of the ring open-
ing of epoxides with aliphatic and aromatic amines under
solvent free conditions with microwave irradiation by
N-fluorobenzenaminium tertrafluoroborate in situ generated
by Selectfluor and aniline. We obtained an excellent yield of
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Table 3 Ring-opening of different epoxides with aniline using Selectfluor as the catalyst and microwave irradiationa
Entry
1
Epoxide
Product
Isolated yieldb(%)
69
2
3
88c
64d
4
5
84
82
6
65
a
Selectfluor (2 mol%), aniline (2 mol%), epoxides (2 mmol) and aniline (2.0 mmol) were microwave irradiated at 200 W and 70 °C for 10 min.
Isolated yield after purification by column chromatography. Regioisomeric ratio of compound 11a and 11b is 77 : 23. Regioisomeric ratio
b
c
d
of compound 13a and 13b is 79 : 21.
Fig. 4 Ortep diagram of compound (S)-naphthyloxy-β-aminoalcohol
20·HCl (50% thermal ellipsoid) color code: black and white octants: C;
red octants: O; blue octants: N; green octants: chlorine; grey balls.
Scheme 2 Synthesis of enantiopure naphthyloxy-β-amino alcohols 20
and 21.
47, 7715; (e) Cu(OTf)2: G. Sekar and V. K. Singh, J. Org. Chem.,
1999, 64, 287; ( f ) Bi(OTf)3: T. Ollevier and G. Lavie-Compin,
Tetrahedron Lett., 2004, 45, 49; (g) Sm(OTf)3: J. S. Yadav,
A. R. Reddy, A. V. Narsaiah and B. V. S. Reddy, J. Mol. Catal. A:
Chem., 2007, 261, 207.
K. B. Reddy and J. S. Yadav, Synthesis, 2003, 2298; (k) ZrCl4:
A. K. Chakraborti and A. Kondaskar, Tetrahedron Lett., 2003,
44, 8315; (l) J. R. Rodríguez and A. Navarro, Tetrahedron
Lett., 2004, 45, 7495; (m) IrCl3: J. Agarwal, A. Duley, R. Rani
and R. K. Peddinti, Synlett, 2009, 2790.
10 (a) Ti(OPri)4: S. Sagava, H. Abe, Y. Hase and T. Inaba, J. Org. Chem.,
1999, 64, 4962; (b) DIPT (diisopropoxyaluminiumtrifluoroacetate):
S. Rampalli, S. S. Chaudhari and K. G. Akamanchi, Synthesis,
2000, 78; (c) Al(OC(CF3)2R)3: Y. Li, Y. Tan, E. Herdtwick,
M. Cokoja and F. E. Kühn, Appl. Catal., A, 2010, 384, 171.
11 (a) Et2AlNHR: L. E. Overman and L. A. Flippin, Tetrahedron
Lett., 1981, 22, 196; (b) Silicon amides: A. Papini, I. Ricci,
9 (a) Ph4SbOTf: M. Fujiwara, M. Imada, A. Baba and
H. Matsuda, Tetrahedron Lett., 1989, 30, 739; (b) Ln(OTf)3:
M. Chini, P. Crotti, L. Favero, F. Macchia and M. Pineschi,
Tetrahedron Lett., 1994, 35, 433; (c) Yb(OTf)3: M. Meguro,
N. Asao and Y. Yamamoto, J. Chem. Soc., Perkin Trans. 1, 1994,
2597; (d) LiOTf: J. Augé and F. Leroy, Tetrahedron Lett., 1996,
3950 | Catal. Sci. Technol., 2014, 4, 3945–3952
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Table 4 Recycling and reusability of in situ generated catalyst 1 for ring
opening of cyclohexene oxide with aniline with microwave irradiationa
20 M. M. Heravi, B. Baghernejad and H. A. Oskooie, Catal. Lett.,
2009, 130, 547.
21 G. Kumar, A. P. Singh and R. Gupta, Eur. J. Inorg. Chem.,
2010, 5103.
22 G. R. Krishnan and K. Sreekumar, Polymer, 2008, 49, 5233.
23 S. Wei, K. A. Stingl, K. M. Weiß and S. B. Tsogoeva, Synlett,
2010, 707.
24 A. Najmodin and R. S. Mohammad, Org. Lett., 2005, 17,
3649.
25 G. D. Yadav, M. S. Chauhan and S. Singh, Synthesis, 2014,
629.
Entry
Recycles
Yieldb(%)
1
2
3
4
5
0
1
2
3
4
98
95
91
86
40
26 (a) X.-L. Hou, J. Wu, L.-X. Dai, L.-J. Xia and M.-H. Tang,
Tetrahedron: Asymmetry, 1998, 9, 1747; (b) G. Bartoli,
M. Bosco, A. Carlone, M. Locatelli, M. Massaccesi,
P. Melchiorre and L. Sambri, Org. Lett., 2004, 6, 2173; (c)
C. Schneider, A. R. Sreekanth and E. Mai, Angew. Chem., Int.
Ed., 2004, 43, 5691; (d) F. Carrée, R. Gil and J. Collin, Org.
Lett., 2005, 7, 1023; (e) S. Azoulay, K. Manabe and
S. Kobayashi, Org. Lett., 2005, 7, 4593; ( f ) C. Ogawa,
S. Azoulay and S. Kobayashi, Heterocycles, 2005, 66, 201; (g)
R. I. Kureshy, S. Singh, N. H. Khan, S. H. R. Abdi,
E. Suresh and R. V. Jasra, Eur. J. Org. Chem., 2006, 1303;
(h) K. Arai, M. M. Salter, Y. Yamashita and S. Kobayashi,
Angew. Chem., Int. Ed., 2007, 46, 955; (i) K. Arai,
S. Lucarini, M. M. Salter, K. Ohta, Y. Yamashita and
S. Kobayashi, J. Am. Chem. Soc., 2007, 129, 8103; ( j)
H. Bao, J. Zhou, Z. Wang, Y. Guo, T. You and K. Ding,
J. Am. Chem. Soc., 2008, 130, 10116; (k) B. Gao, Y. Wen,
Z. Yang, X. Huang, X. Liu and X. Feng, Adv. Synth. Catal.,
2008, 350, 385; (l) H. Bao, J. Wu, H. Li, Z. Wang, T. You
and K. Ding, Eur. J. Org. Chem., 2010, 6722; (m) M. Martin,
A. El Hellani, J. Yang, J. Collin and S. Bezzenine-Lafollée,
J. Org. Chem., 2011, 76, 9801; (n) B. Plancq and T. Ollevier,
Chem. Commun., 2012, 48, 3806; (o) M. Kumar,
R. I. Kureshy, S. Saravanan, S. Verma, A. Jakhar,
N. H. Khan, S. H. R. Abdi and H. C. Bajaj, Org. Lett., 2014,
7, 2798.
27 R. Gedye, F. Smith, K. Westaway, H. Ali, L. Baldisera,
L. Laberge and J. Rousell, Tetrahedron Lett., 1986, 27, 279.
28 (a) R. A. Abramovich, Org. Prep. Proced. Int., 1991, 23, 683;
(b) S. Caddick, Tetrahedron, 1995, 51, 10403; (c)
D. M. P. Mingos and D. R. Baghurst, Chem. Soc. Rev., 1991,
20, 1; (d) K. D. Raner, C. R. Strauss, R. W. Trainor and
J. S. Thorn, J. Org. Chem., 1995, 60, 2456; (e) C. R. Strauss
and R. W. Trainor, Aust. J. Chem., 1995, 48, 1665; ( f )
D. Dallinger and C. O. Kappe, Chem. Rev., 2007, 107, 2563.
29 (a) A. K. Chkraborti, A. Kondaskar and S. Rudrawar,
Tetrahedron, 2004, 60, 9085; (b) T. Ollevier and E. Nadeau,
Tetrahedron Lett., 2008, 49, 1546; (c) R. I. Kureshy, S. Singh,
N. H. Khan, S. H. R. Abdi, S. Agarwal, V. J. Mayani and
R. V. Jasra, Tetrahedron Lett., 2006, 47, 5277; (d) H. Zuo, Z.-B. Li,
B.-X. Zhao, J.-Y. Miao, L.-J. Meng, K. Jang, C. Ahn, D.-H. Lee and
D.-S. Shin, Bull. Korean Chem. Soc., 2011, 32, 2965.
a
The in situ generated catalyst 1 (2 mol%), cyclohexene oxide
(8 mmol) and amines (8.0 mmol) were microwave irradiated at
200 W and 70 °C for 10 min. Yield after purification by column
chromatography.
b
M. Taddei, G. Seconi and P. Dembach, J. Chem. Soc., Perkin
Trans. 1, 1984, 2261; (c) R2NMgBr: M. C. Carre,
J. P. Houmounou and P. Caubere, Tetrahedron Lett., 1985,
26, 3107; (d) R3′PbNR2: J.-I. Yamada, M. Yumoto and
Y. Yamamoto, Tetrahedron Lett., 1989, 30, 4255; (e) Cu
amide: Y. Yamamoto, N. Asao, M. Meguro, N. Tsukade,
H. Nemoto, N. Adayari, J. G. Wilson and H. Nakamura,
J. Chem. Soc., Chem. Commun., 1993, 1201; ( f ) LiNtf2:
J. Cossy, V. Bellosta, C. Hamoir and J.-R. Desmurs,
Tetrahedron Lett., 2002, 43, 7083.
12 (a) Variety of metal salts: M. Chini, P. Crotti and F. Macchia,
Tetrahedron Lett., 1990, 31, 4661; (b) P.-Q. Zhao, L.-W. Xu
and C.-G. Xia, Synlett, 2004, 846; (c) CuBF4: A. Kamal,
R. Ramu, M. A. Azhar and G. B. R. Khanna, Tetrahedron
Lett., 2005, 46, 2675; (d) Y(NO3)3·6H2O: M. J. Bhanushali,
N. S. Nandurkar, M. D. Bhor and B. M. Bhanage,
Tetrahedron Lett., 2008, 49, 3672.
13 U. Das, B. Crousse, V. Kesavan, D. Bonnet-Delpon and
J.-P. Begue, J. Org. Chem., 2000, 65, 6749.
14 J. S. Yadav, B. V. S. Reddy, A. K. Basak and A. V. Narasaiah,
Tetrahedron Lett., 2003, 44, 1047.
15 M. Curini, F. Epifano, M. C. Marcotullio and O. Rosati, Eur.
J. Org. Chem., 2001, 4149.
16 M. M. Mojtahedi, M. R. Saidi and M. Bolourtchian, J. Chem.
Res., Synop., 1999, 128.
17 (a) H. Kotsuki, T. Shimanouchi, M. Teraguchi, M. Kataoka,
A. Tatsukawa and H. Nishizawa, Chem. Lett., 1994, 2159; (b)
A. K. Chakraborti, S. Rudrawar and A. Kondaskar, Org.
Biomol. Chem., 2004, 2, 1277.
18 (a) G. H. Posner and D. Z. Roger, J. Am. Chem. Soc., 1977, 99,
8208; (b) M. D. Pujol and Y. Harrak, Tetrahedron Lett., 2002,
43, 819; (c) W. M. Xue, M. C. Kung, A. I. Kozlov, K. E. Popp
and H. H. Kung, Catal. Today, 2003, 85, 219.
30 (a) R. P. Singh and J. M. Shreeve, Chem. Commun., 2001,
1196; (b) A. A. Gakh, S. V. Romaniko, B. I. Ugrak and
A. A. Fainzilberg, Tetrahedron, 1991, 47, 7447; (c) D. Cahard,
19 R. I. Kureshy, S. Singh, N. H. Khan, S. H. R. Abdi, E. Suresh
and R. V. Jasra, J. Mol. Catal. A: Chem., 2007, 264, 162.
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Paper
C. Audouard, J. C. Plaquevent and N. Roques, Org. Lett.,
Catalysis Science & Technology
31 M. Tokunaga, J. F. Larrow, F. Kakiuchi and E. N. Jacobsen,
Science, 1997, 277, 936.
32 A. Robin, F. Brown, N. Bahamontes-Rosa, B. Wu, E. Beitz,
J. F. J. Kun and S. L. Flitsch, J. Med. Chem., 2007, 50, 4243.
2000, 2, 3699; (d) M. Abdul-Ghani, R. E. Banks,
M. K. Besheesh, I. Sharif and R. G. Syvret, J. Fluorine Chem.,
1995, 73, 255.
3952 | Catal. Sci. Technol., 2014, 4, 3945–3952
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