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Y.B. Huang et al. / Chinese Chemical Letters 22 (2011) 1055–1058
Table 3
The MBH reaction of different aromatic aldehydes with methyl acrylatea,b
.
Entry
Ar
Time (h)
Product
Yieldc (%)
Entry
Ar
Time (h)
Product
Yieldc (%)
1
2
3
4
5
Ph-
24
6
5a
5b
5c
5d
5e
92
96
76
72
80
6
7
8
9
4-Cl-C6H4-
4-Br-C6H4-
2-Naphthyl-
2-Furyl-
24
24
24
24
5f
82
83
78
85
4-NO2-C6H4-
4-CH3-C6H4-
4-CH3O-C6H4-
4-OH-C6H4-
5g
5h
5i
32
32
32
a
Reaction condition: arylaldehyde (2.0 mmol), methyl acrylate (6.0 mmol), DABCO (2.0 mmol), catalyst 2 (20 mol%), DMSO (5.0 mL),
reaction temperature was 25 8C.
Catalyst was recovered by fluorous solid phase extraction.
b
c
Isolated yield from column chromatography.
2. Conclusions
In summary, a kind of fluorous tag thiourea organocatalyst 1-[4-(perfluorooctyl)phenyl]-3-phenylthiourea could
effectively accelerate the DABCO-promoted Morita–Baylis–Hillman reaction of aromatic aldehydes with methyl
acrylate. And the catalyst can be easily recovered by F-SPE for reuse. Application of this catalyst for other reactions
are under investigation and will be reported in due course.
Acknowledgments
We thank the project of ‘‘Excellence Initiative’’ and ‘‘Zijin Star’’ in NJUST, ‘‘Doctoral Fund of Ministry of
Education of China’’ (No. 200802881024), and ‘‘National Natural Science Foundation of China’’ (No. 20902047) for
financial support.
References
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[10] General procedure for the MBH reaction and the recycle of catalyst by F-SPE: the mixture of benzaldehyde (2.0 mmol), fluorous thiourea
catalyst 2 (0.4 mmol) and DABCO (2.0 mmol) in DMSO (5 mL) was added into methyl acrylate (6.0 mmol) at room temperature. The resulting
mixture was stirred vigorously for 24 h. After finishing reaction, the crude product was evaporated by reduced pressure in order to remove
excess methyl acrylate. The residue was loaded onto a FluoroFlash1 silica gel cartridge (5 g), then eluted by methanol:water (75:25) 8–10 mL
in order to separate non-fluorous organic components from the mixture. Then the cartridge was eluted by pure methanol 15–20 mL so as to
recover the catalyst. Meanwhile, the first elutant was evaporated to obtain the crude. The remains was purified by column chromatography on
silica gel using mixtures of petroleum ether and ethyl acetate (70:30) as elutant to give the adducts 5a–5i in pure form. All compounds were
characterized by MS, 1H NMR and 13C NMR, and were compared with the authentic samples.