In Conia-ene reactions proceeding via alkyne activation, a suitable late transition metal (Au, Ag, Pt, Pd) coordinates to the alkyne and increases its electrophilicity; thus, the enol tautomer of the carbonyl can attack more readily. Toste et al. pioneered two of the first examples of alkyne activation in 2004. Using a cationic Au(I) complex, the authors formed a wide variety of cyclized products from linear β-ketoester starting materials. Notably, the reactions are run under mild conditions and give high diastereoselectivity. Moreover, by shortening the alkyne tether from three carbons to two, substituted cyclopentenes can also be accessed.