Allene-Based Gold-Catalyzed Stereodivergent Synthesis of Azapolycyclic Derivatives of Unusual Structure

The present study provides insights into the manner in which the configuration of β-aminoallene precursors affects their gold-catalyzed cyclization reactions. The reactivity can be switched by using indolizidinone-tethered β-aminoallenes bearing the syn- or the anti-disposition of both protons at the α- and β-allenic stereocenters. Fused heterocycles (seven examples, 60-75% yields) are obtained from the syn-precursors, while a dimerization-aminoketalization-spirocyclization sequence to afford benzo[b]pyrrolo[3,2,1-ij][1,7]naphthyridin-1-ones (four examples, 34-48% yields) can be achieved starting from their anti-isomers.Support for this work by MINECO and FEDER (Projects CTQ2012-33664-C02-01, CTQ2012-33664-C02-02, CTQ2015- 65060-C2-1-P, and CTQ2015-65060-C2-2-P) is gratefully acknowledgedPeer Reviewe