Abstract
Oxydation of 2 with iodine followed by acylation leads to β‐lactamdisulfides of type 3. Compounds 3 can be transformed into alcohols 4 by reductive alkylation with ethylenoxide and zinc/acetic acid. Compounds 4 are used as starting materials for the synthesis of N‐acylderivatives 12 of 7‐amino‐ceph‐3‐em‐4‐carboxylic acid (D).