Studies on the Synthesis of Macrocyclic Allenes by Ring Closing Metathesis and Doering–Moore–Skattebøl Reaction

Abstract Several efficient synthetic approaches to allenic cyclophanes of the general structure 2 / 3 , which are of interest as chiral ligands or host molecules, are described. The combination of the ruthenium‐catalyzed ring‐closing metathesis and the Doering–Moore–Skattebøl (DMS) reaction using the Seyferth reagent PhHgCBr 3 provided a straightforward access to the allenic cyclophane 8 . The macrocycles 13 and 17 with the allenic bridge between the aromatic units were also obtained efficiently by copper‐promoted S N 2'‐substitution of propargylic acetates and ring‐closing metathesis. Alternatively, macrocyclic allenes can be synthesized by ring‐closing metathesis of α,ω‐bisallenes, as was demonstrated by the formation of the products 20 , 21 , and 23 . (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)