Table 2 Screening of solvents for the negishi cross-coupling. Conditions: 1 M, 80 °C, 20 h, [BnZnBr]: [4-MeC6H4I]: [CoBr2] = 2 : 1 : 0.05;

From: Synthesis of diarylmethanes by means of Negishi cross-coupling enabled by cobalt-solvent coordination

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#

Solvent

Conv. of 2 [%]a)

Selectivity of 3a [%]a)

1

THF

90

91

2

1,4-dioxane

86

90

3

Eucalyptol

61

90

4

DMAc

> 99

> 99

5

DMF

76

88

6

Acetonitrile

81

92

7

NMP

87

92

  1. a determined by GC-MS. THF – tetrahydrofuran, DMAc – N,N-dimethylacetamide, DMF - N,N-dimethylformamide, NMP – N-methyl-2-pyrrolidone.
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