Table 1 Condition screening of the [Rh2]-enabled carbenoid transfer-aerobic oxidation cascade reactiona

From: Bifunctionality of dirhodium tetracarboxylates in metallaphotocatalysis

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Entry

M-cat. (x mol%)

Acid (y equiv.)

T/°C

T/h

Yield of 6a/%b

Yield of 7a/%

1

Rh2(esp)2(2)

–

25

48

62

0

2

Rh2(esp)2(2)

HOAc (1.5)

25

48

73

0

3

Rh2(esp)2(2)

PhCO2H(1.5)

25

48

70

0

4

Rh2(esp)2(2)

rac-BNDHP (1.5)

25

48

0

0

5

Rh2(esp)2(2)

p-TSA (1.5)

25

48

0

0

6

Rh2(esp)2(2)

HOAc (0.1)

25

48

60

0

7

Rh2(OAc)4(2)

HOAc (1.5)

25

48

71

0

8

Rh2(Oct)4(2)

HOAc (1.5)

25

48

72

0

9

Rh2(cap)4(2)

HOAc (1.5)

25

48

Trace

34

10

Rh2(TFA)4(2)

HOAc (1.5)

25

48

15

0

11

Rh2(esp)2(2)

HOAc (1.5)

35

16

81

0

12

Rh2(esp)2(2)

HOAc (1.5)

45

16

78

0

13c

Rh2(esp)2(2)

HOAc (1.5)

35

16

0

98

14d

Rh2(esp)2(2)

HOAc (1.5)

35

16

81

0

15e

Rh2(esp)2(2)

HOAc (1.5)

35

16

72

0

16f

Rh2(esp)2(2)

HOAc (1.5)

35

16

80

0

  1. aUnless otherwise indicated, reaction conditions: 4a (0.20 mmol), 5a (0.30 mmol), metal catalyst, solvent (2 mL), 12 W white LED. Rh2(oct)4: Dirhodium(II) octanoate; Rh2(cap)4: Dirhodium(II) Tetra(caprolactam); Rh2(TFA)4: Dirhodium(II) trifluoroacetate.
  2. bIsolated yield.
  3. cUnder an atmosphere of nitrogen instead of air.
  4. dUnder an atmosphere of pure oxygen instead of air.
  5. e0.24 mmol 5af.
  6. fIn sunlight instead of LED, 8 h. In the radar diagram: T temperature.
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