Cephalosporanate (I) was equilibrated with its delta-2,3 isomer (II) by treatment with Et3N. Isomer (II) was then carefully hydrolyzed to alcohol (III) without formation of the corresponding lactone by-product. The oxidation of alcohol (III) with pyridinium dichromate gave aldehyde (IV), which was subjected to a Wittig condensation with phosphorane (V) to produce the unsaturated E-amide (VI) as the major isomer. Sulfur oxidation with MCPBA, with concomitant double bond isomerization, furnished sulfone (VII). Finally, removal of the benzhydryl protecting group with trifluoroacetic acid, followed by treatment with sodium bicarbonate yielded the title sodium carboxylate salt.