Synthesis of 3-functionalised cephalosporins by photoinitiated bromination. Transformations of 2,2,2-trichloroethyl 1S, 6R, 7R)-3-bromomethyl-7-formamidoceph-3-EM-4-carboxylate, 1-oxide

Article abstract of DOI:10.1016/S0040-4020(01)88547-1

The 3-bromomethyl derivative 2c, obtained by photoinitiated bromination of the corresponding 3-Me compound 1c, has been converted into the antibiotics cephalothin 18 and cephaloridine 20. Reaction of 2c with lithium dimethyl- and diphenyl-cuprate led to the intermediates 22 and 24 respectively. Further transformation of 24 provided the 3-benzyl derivative 27, an isostere of cephaloridine.