Intermolecular Carbosilylation of α-Olefins with C(sp3)-C(sp) Bond Formation Involving Silylium-Ion Regeneration

A regioselective addition of alkynylsilanes across unactivated, terminal alkenes is reported. The reaction is initiated by the capture of a sterically unhindered silylium ion by a silylated phenylacetylene derivative to form a bis(silylated) ketene-like carbocation. This in situ-generated key intermediate is the actual catalyst that maintains the catalytic cycle by a series of electrophilic addition reactions of silylium ions and beta-silicon-stabilized carbocations. The computed reaction mechanism is fully consistent with the experimental findings. This unprecedented two-component carbosilylation establishes a C(sp(3))-C(sp) bond and a C(sp(3))-Si bond in atom-economic fashion.

Automated summary

A regioselective addition reaction of unactivated, terminal alkenes has been reported using alkynylsilanes as the reagent. The reaction is initiated by the capture of a sterically unhindered silylium ion by a silylated phenylacetylene derivative, forming a bis(silylated) ketene-like carbocation. This key intermediate acts as the actual catalyst and undergoes a series of electrophilic addition reactions to maintain the catalytic cycle. The reaction mechanism is consistent with experimental findings and provides an atom-economical method for forming C(sp(3))-C(sp) and C(sp(3))-Si bonds.