Table 3 Optimization of the C–H bond cleavage reaction conditions.

From: Intramolecular C–F and C–H bond cleavage promoted by butadienyl heavy Grignard reagents

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Entry

Organometallic reagent

Reaction temperature

Isolated yield

1

4.0 equiv t-BuLi

−78 °C to r.t.

Trace

2

2.0 equiv Lithium biphenylide

−78 °C to r.t.

0%

3

2.0 equiv Rieke Mg*

−78 °C to r.t.

Trace

4

2.0 equiv Rieke Ca†

−78 °C to r.t.

54%

5

2.0 equiv Rieke Ba†

−78 °C to r.t.

74%

  1. r.t., room temperature
  2. *Rieke metal was prepared by the reaction between AeI2 and K.
  3. †Rieke metal was prepared by the reaction between AeI2 and lithium biphenylide.
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