Lithium Dienolate Generation by α-Regioselective Reaction of (1-Silylallyl)lithiums with Carbon Monoxide

Lithium dienolates of α,β-unsaturated acylsilanes can be conveniently obtained by the reaction of (1-silylallyl)lithiums with carbon monoxide at ambient temperature. This reaction represents a rare example of α-selective C−C bond formation for an ambident 1-silylallyl anion, which may be rationalized by assuming an equilibration process.