Multicomponent Access to Functionalized Mesoionic Structures Based on TFAA Activation of Isocyanides: Novel Domino Reactions

The reactions of azines (isoquinolines, pyridine) with TFAA and isocyanides in a new domino process yield mesoionic acid fluorides with an imidazo[1,2‐a]azine core. This multicomponent reaction has a general character, tolerating a wide range of substitution patterns on each component, and displays an unprecedented arrangement of reaction pathways. The protocol allows the incorporation of a fourth synthetic input by the reaction of a suitable nucleophile (alcohols, thiols, amines) with the acid fluoride moiety.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) Teamwork! Each component cooperatively participates in these new domino processes thereby allowing the formation of five to seven bonds. Unexpected reaction pathways become feasible thanks to the manifold roles played by the three distinct reagents in a precise sequence. Functionalized dipolar compounds are prepared in a single operation that requires only the mixing of the substrates.