Table 1 Optimization of the reaction conditionsa.

From: Phosphorus(III)-assisted regioselective C–H silylation of heteroarenes

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Entry

Variation from the “standard conditions”

Yield of 2a (%)b

1

none

80 (75)c

2

Using BQ instead of DMBQ

58

3

Using Ag2CO3 instead of DMBQ

24

4

Using Cu(OAc)2 instead of DMBQ

12

5

Using PdCl2 instead of Pd(OAc)2

72

6

Using [Rh(cod)Cl]2 instead of Pd(OAc)2

0

7

Using [RuCl2(p-cymene)]2 instead of Pd(OAc)2

0

8

Using [Ir(COD)Cl]2 instead of Pd(OAc)2

0

9

Using cyclohexane instead of toluene

71

10

Using 5, 7-10 instead of 1a

0

11

Using II-V instead of I

0

12

at 100 °C

62

13

Without DMBQ

6

14

Without Pd(OAc)2

0

  1. aStandard conditions: 1a (0.20 mmol), I (1.0 mmol), Pd(OAc)2 (10 mol%), DMBQ (0.7 mmol) in toluene (0.5 mL), 72 h, 120 oC, under Ar. bGC yield. cIsolated yield.
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