Cobalt-mediated cycloisomerization of δ-substituted ε-acetylenic β- ketoesters construction of angular triquinane by a sequence ene/Pauson-Khand reactions

Article abstract of DOI:10.1016/S0040-4020(99)00172-6

The preparation of δ-substituted ε-acetylenic β-ketoesters is fully described. Their cobalt-mediated Conia-ene reactions led to variously functionalized methylenecyclopentanes in high yields land with a moderate control of the 1,4 diastereoselectivity. A sequence involving the cobalt- mediated ene and Pauson-Khand reactions is presented and allowed the construction of the angular triquinane framework.