A novel sequential palladium/ruthenium-catalysed three-component process is described involving allenylation of aryl/heteroaryl iodides to generate (pi -allyl) palladium species which are intercepted by nitrogen nucleophiles to afford 1,6- and 1,7-dienes. Subsequent ring-closing metathesis affords N-heterocycles in good yield. (C) 2001 Elsevier Science Ltd. All rights reserved.
A novel sequential Pd-catalysed termolecular allenylation cascade/Ru catalysed RCM process affords a diverse range of Δ3-aryl/heteroaryl substituted five–seven membered nitrogen and oxygen heterocycles. Furtherelaboration, via 1,3-dipolar cycloaddition, in selected cases, afforded fused heterocyclic ring systems.