Modular Access to Diverse Bridged Indole Alkaloid Mimics via a Gold-Triggered Cascade Dearomative Spirocarbocyclization/[4 + 2] Cycloaddition Sequence

A modular and streamlined synthetic strategy for the generation of bridged indole alkaloid-like heterocycles from easily available building blocks is elaborated. This approach utilizes an Ugi four-component reaction, establishing diversity, followed by an efficient cationic gold-triggered intramolecular cascade non-oxidative dearomative spirocarbocyclization/concerted [4 + 2] cyclization cascade, furnishing these architecturally complex and distinct bridged heterocyclic scaffolds with good diastereoselectivity.