Palladium (II) Mediated Transformation: Exploring Synthetic Methodology for the Synthesis of Cyclopentenones from Tertiary-Cyclobutanois

A new method for the synthesis of ring-fused cyclopentenone is described. The method utilizes the built-in strain of tertiary cyclobutanol to drive the palladium(II)-catalyzed rearrangement to the corresponding ring-fused cyclopentanone followed by Saegusa-Ito reaction to furnish final cyclopentenone product. Extensive efforts to transform this reaction into a catalytic process by screening various palladium(II) sources, ligands, oxidants, bases, solvents and reaction temperatures failed. Interesting and unexpected results were however obtained while exploring copper(II) chloride and copper(II) bromide as potential oxidants.