A synthetic equivalent of the Nazarov reagent, the silyl derivative <b>2</b>, able to undergo base-catalyzed double Michael addition reactions with α,β-unsaturated carbonyl compounds has been developed. The new reagent satisfactorily reacts with unsaturated indolo[2,3-<i>a</i>]quinolizidine lactams to give pentacyclic yohimbinone-type derivatives