Double nucleophilic addition of bis(trimethylsilyl)ketene acetals to carbon–carbon double bonds of pyrazines: formation of polycyclic γ-lactones

The double activation of pyrazines upon their interaction with methyl chloroformate leading in the presence of bis(TMS)ketene acetals to polycyclic N-containing γ-lactones parallels the interaction of the same ketene acetals with metal-activated aromatics. The fundamental role of the two oxygen–silicon bonds is outlined. This result broadens the scope of application of these ketene acetals as potential 1,3-dinucleophiles.