Stereocontrolled Construction of Seven-Membered Carbocycles Using a Combination of Brook Rearrangement-Mediated [3 + 4] Annulation and Epoxysilane Rearrangement

Reactions of δ-silyl-γ,δ-epoxy-α,β-unsaturated acylsilane with alkenyl methyl ketone enolate afford highly functionalized cycloheptenone derivatives via a tandem sequence featuring the combination of Brook rearrangement-mediated [3 + 4] annulation and epoxysilane rearrangement. The reactions using an opposite combination of three and four carbon units, in which an epoxysilane moiety was incorporated in the four-carbon unit, also give satisfactory results. Also, the possibility of chirality transfer from epoxide to remote positions via the tandem sequence using an optically active epoxide has been demonstrated.