Regioselective Hydroalkylation of Vinyl- and Allylsilanes as Well as Vinylgermanes under Ni–H Catalysis

Abstract

A Ni–H-catalyzed hydroalkylation of vinylsilanes and -germanes as well as allylsilanes with unactivated alkyl iodides is reported. Unlike related reactions of styrene or vinyl boronate esters, the addition across the C–C double bond proceeds with anti-Markovnikov selectivity to deliver the linear regioisomer. Mechanistic control experiments support a radical mechanism, and a competition experiment reveals that the chemoselectivity is in favor of the vinyl over the allyl group.

Ligand-Controlled On–Off Switch of a Silicon-Tethered Directing Group Enabling the Regiodivergent Hydroalkylation of Vinylsilanes under Ni–H Catalysis

“…Despite considerable advancements in the particularly challenging C­(sp 3 )–C­(sp 3 ) bond formation, the regioselectivities of these reactions are typically dictated by the substrate. The addition of a Ni–H complex to an internal or terminal alkene usually leads to isomerization and chain walking of the alkene unit to the terminal position (Scheme , eq 1). ,, To achieve branched selectivity with α-olefins, functional groups such as amide, boryl, carbamate, or ether groups are needed to stabilize the internal nickel intermediate (Scheme , eq 2). Furthermore, Shu and co-workers disclosed two efficient protocols that enable branched-selective hydroalkylation of terminal alkenes by the use of remote directing groups (DGs) (Scheme , eq 3) …”