Scheme 4. Catalytic Cycle Proposed for the Reaction of 1a with NBS to Give Cyclopentanones CY1–4.

The alternative cycle to afford epoxides EP1–4 is also indicated. Intermediates IN1–4 could not be located at any level of theory. The values between brackets are relative free energies corresponding to preliminary studies with the 1 series calculated at the wb97xd/def2tzvp/pcm=toluene//wb97xd/def2svp level of theory (for details, see the Supporting Information).