Table 1 Optimization of reaction conditions^a

1

–

Cat-1 (10)

DCM

–

32

95:5

2

2

–

Cat-2 (10)

DCM

–

49

90:10

7

3

–

Cat-3 (10)

DCM

–

50

95:5

3

4

CuTC (10)

Cat-1 (10)

DCM

–

53

84:16

4

5

CuTC (10)

Cat-2 (10)

DCM

–

60

69:31

64

6

CuTC (10)

Cat-3 (10)

DCM

–

70

66:34

87

7

CuTC (10)

Cat-4 (10)

DCM

–

64

90:10

<5

8

CuTC (10)

Cat-5 (10)

DCM

–

31

80:20

<5

9

CuTC (10)

Cat-6 (10)

DCM

–

67

67:33

71

10

CuTC (10)

Cat-7 (10)

DCM

–

50

95:5

<5

11

CuI (10)

Cat-3 (10)

DCM

–

54

86:14

71

12

Cu₂O (10)

Cat-3 (10)

DCM

–

36

95:5

54

13

Cu(MeCN)₄PF₆ (10)

Cat-3 (10)

DCM

–

52

70:30

16

14

CuTC (10)

Cat-3 (10)

THF

–

67

66:34

85

15

CuTC (10)

Cat-3 (10)

Toluene

–

45

87:13

23

16

CuTC (10)

Cat-3 (10)

DCE

–

40

75:25

22

17

CuTC (10)

Cat-3 (10)

CH₃CN

–

70

60:40

79

18

CuTC (10)

Cat-3 (10)

acetone

–

64

67:33

85

19

CuTC (10)

Cat-3 (10)

PhCl

–

45

66:34

75

20

CuTC (10)

Cat-3 (10)

1,4-dioxane

–

71

66:34

83

21^d

CuTC (10)

Cat-3 (10)

DCM

–

70

60:40

90

22^{d, e}

CuTC (10)

Cat-3 (10)

DCM

–

40

70:30

92

23^d

CuTC (10)

–

DCM

L1

29

80:20

15

24^d

CuTC (10)

Cat-3 (10)

DCM

L1

40

60:40

42

25^d

CuTC (10)

Cat-3 (10)

DCM

L2

43

75:25

4

26^d

CuTC (10)

Cat-3 (10)

DCM

L3

56

75:25

17

27^d

CuTC (10)

Cat-3 (20)

DCM

–

72

80:20

93

28^{d, e}

CuI (15)

Cat-3 (30)

DCM

–

62

78:22

79

29^{d, e}

CuTC (15)

Cat-3 (30)

DCM

–

72

70:30

90

30^{d, e}

CuTC (10)

Cat-3 (25)

DCM

–

71

90:10

94

31^{d, e}

CuTC (10)

Cat-3 (30)

DCM

–

70

92:8

85