Scheme 1. Synthesis of a propargylamine from a secondary amine, formaldehyde, and a terminal acetylene. promoted by the addition of copper salts.['] Dialkyl-substituted acetylenes undtrgo intramolecular reactions with in situ generated iminium ions only with the assistance of external nucleophiles such as I-.[31 Nucleophilic assistance is not needed for the aminomethylations of the more reactive propargylsilanes,
