The β-amino-substituted α,β-unsaturated Fischer carbene complexes 3 are readily available by a four step one-pot procedure from terminal alkynes, chromium hexacarbonyl and secondary amines (24 examples with yields of 68−99% and 7 examples with yields of 26−63%). The formal [3+2] cycloadditions of complexes 3 with different alkynes including diynes and enynes performed in donor solvents such as pyridine or acetonitrile afforded highly substituted 5-(dialkylamino)-3-ethoxycyclopentadienes 7, generally in medium to excellent yields (25 examples with yields of 60−95% and 7 examples with yields of 18−53%). The steric and electronic effects of the substituents on the carbene complexes and the incorporated alkynes on the regio-and stereoselectivity of the ring-forming reaction have been elaborated. An interesting 1,5-or, more likely, 1,2-migration of the dimethylamino group was observed for 5-(dimethylamino)-3-ethoxycyclopentadienes with trimethylsilyl and iPr substituents at C-5. Attempted asymmetric syntheses of cyclopentadienes 7 from complexes 3 with chiral amino groups or substituents were only moderately successful. At a center of chirality in the secondary amino group, complexes of type 3 gave compounds 7 with diastereomeric excesses of, at best, 59% in yields of