We report geometry-dependent cyclizations of o-alkynylaryl ketoximes and nitrones catalyzed by gold complexes. (E)-Ketoximes undergo N-attack to give isoquinoline-N-oxides. In sharp contrast, (Z)-ketoximes undergo unprecedented O-nucleophilic attack, followed by a redox cascade leading to a novel catalytic entry to isoindoles of diverse scope. The structure of an isoindole was unambiguously supported by X-ray crystallography. We demonstrated the generality of the isoindole synthesis from either (Z)-oximes or nitrones, and presented a mechanistic model of this redox cascade based on the reaction profiles of various substrates.

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Just another Mannich Monday: A cascade intramolecular redox‐pinacol‐Mannich‐Michael reaction sequence catalyzed by gold complexes can be used to generate a variety of structures including spirocycles, 1‐aminoindanes, and 5,6‐fused azabicycles that have a quaternary carbon center. The reaction is characterized by complete atom‐economy, high diastereoselectivity, and remarkable efficiency through tandem reactions.

Mannich und mehr: Eine Sequenz aus intramolekularer Redox‐, Pinacol‐, Mannich‐ und Michael‐Reaktion führt unter Goldkatalyse zu verschiedenartigen Strukturen mit quartären Kohlenstoffzentren, z. B. Spirocyclen, 1‐Aminoindanen und anellierten 5,6‐Azabicyclen. Die Reaktion zeichnet sich durch vollständige Atomökonomie, hohe Diastereoselektivität und eine erstaunliche Effizienz aus.

A comparative study on the Au(I)-catalyzed and IBr-promoted tandem cyclization of 1,5-enyne was reported. This study provides a meaningful mechanistic insight to the concerted nature of this tandem reaction and also provides interesting applications in the synthesis of 7/5-or 8/5-fused bicycles and biaryls.