Table 1 Optimization of reaction conditionsa

From: Facile access to benzofuran derivatives through radical reactions with heteroatom-centered super-electron-donors

View full size image

Entry

Base

Solvent

T (°C)

Yield (%)b

1

tBuOK

DME

30

16

2

KHMDS

DME

30

<5

3

NaHMDS

DME

30

17

4

LiHMDS

DME

30

71

5

LDA

DME

30

76

6

Cs2CO3/NaOH/DBU/DIEA, etc 

 DME

30

0

7

LDA

THF

30

65

8

LDA

CH3CN

30

22

9

LDA

MTBE

30

20

10

LDA

DMF

30

27

11

LDA

DMSO

30

60

12

LDA

CH2Cl2

30

0

13

LDA

DME

50

80

14

LDA

DME

60

74

  1. aUnless otherwise specified, the reactions were carried out using 1a (0.10 mmol), HPPh2 (0.20 mmol), base (0.20 mmol), solvent (2.0 mL) for 8 h under N2. H2O2 (0.25 mmol) was added into reaction system at 0 °C, then the system was stirred at 30 °C for 1 h. bIsolated yield of 3a. DME = 1,2-Dimethoxyethane. HMDS hexamethydisilylamine, THF tetrahydrofuran, MTBE methyl tert-butyl ether.
Back to article page