The cyclization of terminalalkynes with homopropargylicamines in the presence of a rhodium complex as catalyst leads to the formation of (E)-3-alkylidene-1-pyrrolines. The reaction tolerates a wide range of functional groups on the terminalalkynes. The formation of a vinylidene-rhodium complex, followed by the intermolecular nucleophilic attack of a homopropargylicamine nitrogen on the α-carbon