Allenynes exhibited different modes of cyclizations depending on metallic c
atalysts. Palladium compounds would catalyze 1,7-allenynes to the correspon
ding 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. (C) 2
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