3-(3-Substituted prop-1-enyl)cephalosporins

The synthesis of cephalosporin derivatives possessing a 3-substituted prop-1-enyl group at the 3 position is described. This was achieved using the reaction of vinylmagnesium chloride with the 3-formyl derivatives 1 to give a vinylcarbinol which readily underwent allylic rearrangements to give the desired side chains. The new derivatives exhibited potent in vitro and in vivo antibacterial activity.