Ruthenium-catalyzed intramolecular homo-diels-alder reaction of alkyne-tethered norbornadienes. An entry to fused angular triquinanes.
2-(pent-4-ynyl)norbornadienes undergo an intramolecular [2+2+2] cycloaddition in the presence of (nbd)RuCl2(PPh3)2 as a catalyst affording annelated deltacyclenes in good to excellent yields. The usefulness of the reaction is illustrated by the straighforward conversion of pentacyclene 2a into the angularly fused triquinane 19.
Tenaglia
Alphonse
A
Laboratoire de Synthèse Asymétrique, UMR 6180 CNRS, Université d'Aix-Marseille P. Cézanne, Faculté des Sciences et Techniques de St Jérôme, Case A62, Avenue Escadrille Normandie Niemen, 13397 Marseille Cedex 20, France. alphonse.tenaglia@univ-cezanne.fr
Gaillard
Sylvain
S