摘要:
                                Hexamethyl-, hexaethyl- and hexabutyl-ditin add to a variety of allenes in the presence of Pd(PPh3)4; the reaction is reversible.  Trimethylsilyltrimethyl- and -tributyl-stannane also add under comparable conditions, the silyl moiety becoming attached to the central carbon atom of the allene skeleton; this reaction is, however, apparently not reversible.