Table 1 Optimizing the reaction conditions

From: A theory-driven synthesis of symmetric and unsymmetric 1,2-bis(diphenylphosphino)ethane analogues via radical difunctionalization of ethylene

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Entry

Photocatalyst

x

y

light

yielda (%)

1

Ir(ppy)3

0.1

1

Blue

90

2

[Ir{dF(CF3)ppy}2(dtbbpy)]PF6

0.1

1

Blue

33

3

[Ir(ppy)2(dtbbpy)]PF6

0.1

1

Blue

90

4

[Ru(bpy)3](PF6)2

0.1

1

Blue

3

5

[Ir(ppy)2(dtbbpy)]PF6

0.1

1

–

56

6b

[Ir(ppy)2(dtbbpy)]PF6

0.1

1

Blue

81

7c

[Ir(ppy)2(dtbbpy)]PF6

0.1

1

Blue

78

8

[Ir(ppy)2(dtbbpy)]PF6

0.5

0.2

Blue

88 (82d)

9

–

0.1

–

Blue

74

10

–

0.1

–

White

65

11e

–

0.5

–

White

(74d)

  1. Conditions: photocatalyst (y mol%), 1a (x mmol), 2a (x mmol), DBU (1.0 equiv), ethylene (10 atm), DCE (0.33 M), rt, 4 h, and two LEDs
  2. aYields were determined via 1H NMR analysis using 1,1,2,2-tetrachloroethane as the internal standard
  3. b5 atm of ethylene was used
  4. c1 atm of ethylene (balloon) was used
  5. dIsolated yields
  6. eReaction time: 24 h. ppy: 2-phenylpyridine, dF(CF3)ppy: 2-(2,4-difluorophenyl)-5-trifluoromethylpyridine, dtbbpy: 4,4′-bis(1,1-dimethylethyl)-2,2′-bipyridine, bpy: 2,2′-bipyridine
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