Investigation of the scope of an enantioselective Co-mediated O→C rearrangement reaction

A series of enantiomerically enriched functionalised pyrans bearing a dicobalt hexacarbonyl-alkyne moiety have been subjected to a Lewis acid mediated rearrangement to carbocyclic ketones. This process was found to provide cyclohexanones with good enantioselectivity, however, cyclobutanones were generated with complete loss of enantiocontrol.