Abstract: A process for the production of a 3-vinylcephalosporin compound of formula I wherein R1 and R2 denote hydrogen or an organic group by a Wittig reaction reacting first a compound of formula II with a compound of formula P(R4)3 or P(OR4)3 to produce a compound of formula III and secondly reacting the compound of formula III with a weak base of formula or of formula R10—COO−W+ wherein R5 is hydrogen, alkly or aryl and R6 and R7 are each an activated group of formula —COOR8, —CN, —SO2R8, —COR8 or —CON(R8)2; or R5 and R8 are each aryl and R7 is an activated group of formula —COOR8, —CN, —SO2R8, —COR8 or —CON(R8)2, W+ is an alkali metal cation and R10 is alkyl or aryl to produce a compound of formula IV and finally reacting a compound of formula IV with a compound of formula V to produce a compound of formula I.

Abstract: A process for the production of 3-vinylcephalosporin compounds of formula 1

Abstract: A process for the production of a 3-vinylcephalosporin compound of formula I wherein R1 and R2 may be the same or different and denote hydrogen or an organic radical, which comprises subjecting a 3-iodomethyl-cephalosporin to a Wittig reaction in the presence of a weak base.