Entry

Catalyst

Solvent

Temp(℃)

Time(h)

Yield^a(%)

1

No base

EtOH

75

2

NR^b

2

HBF₄ (20 mol%)

EtOH

75

2

73

3

[Bmim]BF₄ (20 mol%)

EtOH

75

2

85

4

[Bmim]BF₄ (20 mol%)

H₂O

75

2

NR^b

5

[Bmim]BF₄ (20 mol%)

CH₃CO₂Et

75

2

45

6

[Bmim]BF₄ (20 mol%)

CH₂Cl₂

75

2

35

7

[Bmim]BF₄ (20 mol%)

CH₃CN

75

2

56

8

[Bmim]BF₄ (20 mol%)

MeOH

75

2

52

9

[Bmim]BF₄ (20 mol%)

Toluene

75

2

32

10

[Bmim]BF₄ (20 mol%)

EtOH

75

5

85

11

[Bmim]BF₄ (20 mol%)

EtOH

80

2

84

12

[Bmim]BF₄ (20 mol%)

EtOH

65

2

72

13

[Bmim]BF₄ (30 mol%)

EtOH

75

2

85