Download PDF Opens in a new window. Article suggestions will be shown in a dialog on return to ScienceDirect. ... Please enable JavaScript to use all the features on this page. ... The 1,7-bis(trimethylsilyl)hepta-2,5-diyne reacts with iminium ions generated in situ from primary alkyl- or primary functional amines by a double aminomethylation–desilylation process leading to N-substituted 3,5-divinylidenepiperidines. ... Le 1,7-bis(triméthylsilyl)hepta-2,5-diyne ...