The transformation of 2-imidazolines into 1,2,3,4-tetrahydropyrrolo[1,2-]pyrazines has been realized. A pseudo-three-component reaction of 2-imidazolines with terminal electron-deficient alkynes (2 equiv) first generates imidazolidines, containing an -vinylpropargylamine fragment. The latter can then undergo a base-catalyzed domino aza-Claisen rearrangement/cyclization reaction sequence, simultaneously constructing pyrrole and pyrazine rings. The process works in a broad substrate scope, delivering pyrrolo[1,2-]pyrazines in good to excellent yields (45-90%). This two-step approach can be carried out in a one-pot fashion without a noticeable decrease in yield. Remarkably, a three-component protocol for the introduction of two different alkynes has been also developed.
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