Rhodium(I)-Catalyzed [2+2], [2+2+2], and [2+2+2+2] Cycloadditions of Dienes or Alkynes with a Bis-ene

A novel metal-catalyzed, all-alkene [2+2+2] cycloaddition reaction involving a strained and conformationally restricted bis-ene and a diene is reported. Modification of the catalyst leads to competition with a diene-ene [2+2] reaction, and when an alkyne was used in place of the diene, [2+2+2] and [2+2+2+2] cycloaddition reactions occurred involving the bis-ene and 1 or 2 equiv of the alkyne