Table 1 Optimization of the reaction conditions

From: Synthesis of benzoheterocycles by palladium-catalyzed migratory cyclization through an unexpected reaction cascade

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Entry

Variations from standard conditionsa (shown above)

2a:2a′b

Yield (%)c 2a

1

None

>50:1

94

2

Xantphos

>50:1

41

3

Dppf

>50:1

82

4

Dppe

>50:1

46

5

Dppp

>50:1

13

6

Dppb

>50:1

23

7

Biphep

–

–

8

Toluene instead of DCE

>50:1

47

9

CH2Cl2 instead of DCE

85:15

78

10

CsOAc instead of CsOPiv

74:26

63

11

KOPiv instead of CsOPiv

89:11

72

12

At 60 °C

>50:1

87

  1. a Reaction conditions: 1a (0.20 mmol), Pd(OAc)2 (5 mol% Pd), DPEPhos (10 mol%), CsOPiv (0.4 mmol), and DCE (1.0 mL) at 80 °C for 12 h.
  2. b Ratio was determined by 1H NMR analysis of the crude reaction mixture.
  3. c Isolated yield.
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