Zinc-Mediated Carbene Insertion to C–Cl Bonds
of Chloromethanes and Isolable Zinc(II) Isocyanide Adducts
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Abstract
The zinc adduct {[HB(3,5-(CF<sub>3</sub>)<sub>2</sub>Pz)<sub>3</sub>]Zn}<sup>+</sup>, which was generated
from [HB(3,5-(CF<sub>3</sub>)<sub>2</sub>Pz)<sub>3</sub>]ZnEt and
[Ph<sub>3</sub>C]{B[3,5-(CF<sub>3</sub>)<sub>2</sub>C<sub>6</sub>H<sub>3</sub>]<sub>4</sub>}, catalyzes the activation of C–halogen
bonds of chloromethanes via carbene insertion. Ethyl diazoacetate
serves as the carbene precursor. The presence of {[HB(3,5-(CF<sub>3</sub>)<sub>2</sub>Pz)<sub>3</sub>]Zn}<sup>+</sup> in the reaction
mixture was confirmed by obtaining {[HB(3,5-(CF<sub>3</sub>)<sub>2</sub>Pz)<sub>3</sub>]Zn(CN<sup>t</sup>Bu)<sub>3</sub>}<sup>+</sup> using
CN<sup>t</sup>Bu as a trapping agent. {[HB(3,5-(CF<sub>3</sub>)<sub>2</sub>Pz)<sub>3</sub>]Zn(CN<sup>t</sup>Bu)<sub>3</sub>}<sup>+</sup> loses one zinc-bound CN<sup>t</sup>Bu easily to produce five-coordinate
{[HB(3,5-(CF<sub>3</sub>)<sub>2</sub>Pz)<sub>3</sub>]Zn(CN<sup>t</sup>Bu)<sub>2</sub>}<sup>+</sup>
