Abstract: The three skipped cyclic CI2Hl2 dienediynes, 4, 9-dimethylene-l, 6-~ yclodecadiyne (l),(Z, Z)-4, 1O-cyclododecadiene-l, 7-diyne (2), and 10-methylene-(Z)-4- cycloundecene-1, 7-diyne (3), have been synthesized by cyclization of dilithium salts of diterminal enediynes with the corresponding dihalogenides. This simple approach only worked (with approx. 5% yield) when no CuCl catalyst was used. Besides 1-3, 4, 9- ...