-046Palladium-Catalyzed Carbocyclization/Silastannylation and Distannylation of Bis(allenes).-The first Pd-catalyzed carbocyclization of bis(allenes) leading to five-membered rings via silastannylation and distannylation, respectively, is presented. A striking reversal of stereochemistry is observed changing from silastannylation to distannylation.

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[reaction: see text] The arylative cyclization of allenyl-aldehydes with aryl iodides and hexa-n-butyldistannane to form substituted cyclopentanols and cyclohexanols by tandem palladium-catalyzed carbostannylation and allylation was achieved under mild conditions.