Chemoselectivities in palladium- and rhodium-catalyzed allenyne cyclizations

Allenynes exhibited different modes of cyclizations depending on metallic catalysts. Palladium compounds would catalyze 1,7-allenynes to the corresponding six-membered carbocycles incorporating a hydrogen or an acetate group depending upon additives used. A rhodium compound catalyzed the cyclization of those allenynes to give the five membered rings chemoselectively.