Silylated azolium salts and their applications in the synthesis of azolines and β-enaminoketones bearing allyl-, vinyl-, and acylsilane or α-silylketone units

Differently silylated 3- or 4-isoxazolines and 3-pyrazolines, bearing versatile vinyl- or allylsilane moieties in various positions of the heterocyclic system, have been synthesized starting from new silylazolium salts by reduction with metal complex hydrides or alkylation with organolithium reagents. On the other hand, the reductive ring-opening of silylated isoxazolium salts with lithium dimethylcuprate led to interesting β-enamino acylsilanes and α′-silylmethyl-β-enaminoketones. These polysynthetic equivalents are useful building blocks in organic synthesis.