New methodology for the conversion of epoxides to alkenes

Epoxides have been transformed in good yields to alkenes by a process involving (i) ring-opening of the epoxide with 2-mercaptobenzothiazole, (ii) oxidation of the derived ß-hydroxy thioethers to the corresponding sulfones, and (iii) thermal or base-promoted fragmentation of these sulfones to alkenes. The stereochemistry of the starting epoxide is transfer-red faithfully to the alkene product, because of the SN2 epoxide ring-opening reactions and the antiperiplanar SO2 elimination reaction of the ß- alkoxysulfinate intermediates. This methodology may form the basis of a new protecting group strategy for alkenes. © 2010 Wiley-VCH Verlag GmbH & Co. KGaA