Abstract
(Chemical Equation Presented) Catalytic cyclization of 1,6-allenynes was achieved by AuPPh <sub>3</sub> SbF <sub>6</sub> (5 mol %) in cold CH <sub>2</sub> Cl <sub>2</sub> (0°C, 0.5-4 h) to form bicyclo[4.3.0]nonadiene products; this cyclization proceeded more efficiently for a substrate bearing R = alkyl (yields >70%). We propose a reaction mechanism involving a 6-endo-dig cyclization of Au(I)-π-alkyne, followed by Nazarov cyclization. © 2007 American Chemical Society.