Regiodivergent Nickel-Catalyzed Hydrosilylation of α-(Fluoroalkyl)styrenes

Key words

nickel catalysis - hydrosilylation - regiodivergent synthesis

Significance

A regiodivergent hydrosilylation reaction of α-(fluoroalkyl)styrenes is reported to occur under mild conditions and with commercially available ligands providing both α- and β-trifluoromethyl-substituted scaffolds. With the bidentate ­ligand BINAP, the reaction proceeds via a ­Markovnikov pathway, selectively forming products with a quaternary center, without any by-products from β-F elimination. In contrast, use of the monodentate PPh₃ ligand promotes the traditional anti-Markovnikov addition pathway.

Comment

Experimental data support a polar mechanism involving the addition of a NiH species. Control experiments demonstrate that the trifluoromethyl group is essential for reactivity; in its absence, only anti-Markovnikov products are formed. DFT analysis confirms that a [1,2]-migratory insertion followed by reductive elimination (Path A) is favored in the presence of BINAP, which the authors attribute to the σ-withdrawing effect of the trifluoromethyl group.

Publikationsverlauf

Artikel online veröffentlicht:
13. September 2024