A Cyclobutadiene Equivalent in the Catalytic Pauson–Khand Reaction

Abstract

A practical and scalable operation: The reaction shown in the scheme, which uses catalytic amounts of hexacarbonyldicobalt, gives access to versatile bicyclic systems, which until now could only be obtained in low quantities by a photochemical process starting from tropolones. An isolation of the primary Pauson–Khand products is not necessary.