Studies on Chromium(0)-Mediated Three Component Cycloaddition Reactions

A novel chromium(0)-promoted three-component alkyne–triene higher-order cycloaddition process is presented. The transformation features tethered alkynes participating in a tandem [6π+2π], [6π+2π] cycloaddition event with cyclic trienes serving as the third reactant. Isomerically homogeneous products possessing five rings and six stereogenic centers are isolated from this reaction in good to excellent yield.