Table 1 Optimization of the reaction conditions

From: Copper-catalyzed highly switchable defluoroborylation and hydrodefluorination of 1-(trifluoromethyl)alkynes

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Entry

Cat. (10 mol%)

Ligand (x equiv.)

Base (y equiv.)

Solvent

Yield(%)a

3

4

5

1

CuSCN

Phen (0.1)

MeOLi (1)

THF

82 (75)b

5

4

2c

CuSCN

Phen (0.1)

MeOLi (1)

THF

74

2

7

3

CuI

Phen (0.1)

MeOLi (1)

THF

33

3

8

4

CuCl

Phen (0.1)

MeOLi (1)

THF

52

2

8

5

CuSCN

Bphen (0.1)

MeOLi (1)

THF

71

8

6

6

CuSCN

PPh3 (0.1)

MeOLi (1)

THF

65

7

3

7

CuSCN

PCy3 (0.1)

MeOLi (1)

THF

16

10

2

8

CuSCN

P(o-tol)3 (0.1)

MeOLi (1)

THF

37

6

1

9

CuSCN

Phen (0.1)

t-BuOK (1)

THF

8

31

15

10

CuSCN

Phen (0.1)

DBU (1)

THF

1

27

18

11

CuSCN

Phen (0.1)

MeOLi (2)

THF

38

43

12

12

CuSCN

Phen (1.0)

MeOLi (2)

THF

35

55

1

13

CuSCN

Phen (1.0)

MeOLi (2)

CH3CN

trace

59

34

14d

CuSCN

Phen (1.0)

MeOLi (2)

CH3CN

trace

93 (71)b

1

15d,e

CuIf

Phen (1.0)

t-BuOK (1.5)

DCM

trace

trace

90 (80)b

  1. Unless otherwise specified, reaction conditions were: the reaction was carried out with 1a (0.2 mmol), 2 (2.0 equiv.), copper catalyst (10 mol%), Phen (0.1–1.0 equiv.), H2O (2.0 equiv.) and base (1.0–2.0 equiv.), in solvent (2.0 mL) at 60 °C, 4 h under nitrogen atmosphere. aThe yield was determined by GC using biphenyl as an internal standard. bIsolated yield in brackets. cUsing 3.0 equiv. B2pin2. dReaction was carried out for 2 h. eUsing 4.0 equiv. H2O at 110 °C. fUsing 20 mol% CuI. Phen 1,10-phenanthroline, Bphen 4,7-diphenyl-1,10-phenanthroline, PPh3 triphenylphosphine, PCy3 tricyclohexyl phosphine, P(o-tol)3: tri(o-tolyl)phosphine.
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