Triynes R-C≡C-CH2CH2-Ar-C≡C-Ar'-CH2CH2-C≡C-R were subjected to Co(I)- or Ni(0)-mediated intramolecular [2+2+2] cycloisomerization to provide corresponding tetrahydropentahelicene, tetrahydrohexahelicene, and tetrahydroheptahelicene in good to moderate yields. The reaction tolerates various substituents at pendant acetylene moieties (R = H, CH3, trimethylsilyl, not triisopropylsilyl) and fluorine in an aromatic part. By contrast, under Rh(I) or Pd(0) catalysis, triyne with the CH2OCH2 tether lost pendant propargyl moieties and an aromatic spiroketal was formed preferentially.