Entry

Brønsted acid

(mol%)

Cobalt salt

Time/h

Yield/%

4

3

1

PhSO3H(10)

-

2

0.7

89.4

2

CH3SO3H(10)

-

2

0.8

87.0

3

CF3SO3H(10)

-

2

2.5

79.9

4

H3PO4(10)

-

2

0.0

90.5

5

H2SO4(10)

-

2

1.6

86.5

6

-

CoCl2

2

0.0

78.9

7

-

Co(NO3)2∙6H2O

2

0.0

98.0

8

-

Co(ClO4)2∙6H2O

2

1.1

95.9

9

-

Co(BF4)2∙6H2O

2

5.8

84.1

10

PhSO3H(10)

CoCl2

2

25.0

56.7

11

PhSO3H(10)

Co(NO3)2∙6H2O

2

1.0

88.1

12

PhSO3H(10)

Co(ClO4)2∙6H2O

2

52.5

45.8

13

PhSO3H(10)

Co(BF4)2∙6H2O

2

46.7

44.8

14

H3PO4(10)

Co(ClO4)2∙6H2O

2

2.9

88.2

15

H3PO4(10)

Co(BF4)2∙6H2O

2

2.7

58.3

16

CF3SO3H(10)

Co(ClO4)2∙6H2O

2

51.5

30.1

17

CF3SO3H(10)

Co(BF4)2∙6H2O

2

78.7

10.8

18

CH3SO3H(10)

Co(ClO4)2∙6H2O

2

63.1

26.7

19

CH3SO3H(10)

Co(BF4)2∙6H2O

2

52.2

28.1

20

H2SO4(10)

Co(ClO4)2∙6H2O

2

18.9

64.8

21

H2SO4(10)

Co(BF4)2∙6H2O

2

32.9

61.2

22

H2SO4(20)

Co(BF4)2∙6H2O

24

76.0

19.6