A method of synthesising a C3-substituted cephalosporin comprising the steps of: (i) generating a compound of formula from a compound of formula (ii) reacting the compound of formula with a thiol of formula (III-1) or (III-2) to yield a compound of formula (IV-1) or (IV-2), and (iii) further processing the compound of formula (IV-1) or (IV-2) to yield a C3-substituted cephalosporin, wherein Z is selected from the group consisting of C 1 -C 20 aliphatic, C 3 -C 20 cycloaliphatic, C 2 -C 20 heteroaliphatic, C 2 -C 20 heterocycloaliphatic, C 6 -C 20 aryl, C 2 -C 20 heteroaryl, and combinations thereof; X is selected from the group consisting of Cl, Br, and I; R 11, R 12, R 13 are the same or different and are independently selected from the group consisting of H, C 1 -C 20 aliphatic, C 3 -C 20 cycloaliphatic, C 2 -C 20 heteroaliphatic, C 2 -C 20 heterocycloaliphatic, C 6 -C 20 aryl, C 2 -C 20 heteroaryl, and combinations thereof; and wherein: the C 1 -C 20 aliphatic, the C 3 -C 20 cycloaliphatic, the C 2 -C 20 heteroaliphatic, and the C 2 -C 20 heterocycloaliphatic is each optionally substituted one or more times with a moiety selected from the group consisting of CN, NO 2, OH, C 1 -C 5 alkoxy, C 1 -C 10 ester, C 1 -C 10 ketone, C 1 -C 10 ketimine, C 1 -C 10 sulfone, C 1 -C 10 sulfoxide, a C 1 -C 10 primary amide, and a C 1 -C 20 secondary amide; and an aryl ring of the C 6 -C 20 aryl and a heteroaryl ring of the C 2 -C 20 heteroaryl is each optionally substituted one or more times with a moiety selected from the group consisting of CN, NO 2, halogen, OH, C 1 -C 5 alkoxy, C 1 -C 10 ester, C 1 -C 10 ketone, C 1 -C 10 ketimine, C 1 -C 10 sulfone, C 1 -C 10 sulfoxide, a C 1 -C 10 primary amide, and a C 1 -C 20 secondary amide. (i) generating a compound of formula from a compound of formula (ii) reacting the compound of formula with a thiol of formula (III-1) or (III-2) to yield a compound of formula (IV-1) or (IV-2), and (iii) further processing the compound of formula (IV-1) or (IV-2) to yield a C3-substituted cephalosporin, wherein Z is selected from the group consisting of C 1 -C 20 aliphatic, C 3 -C 20 cycloaliphatic, C 2 -C 20 heteroaliphatic, C 2 -C 20 heterocycloaliphatic, C 6 -C 20 aryl, C 2 -C 20 heteroaryl, and combinations thereof; X is selected from the group consisting of Cl, Br, and I; R 11, R 12, R 13 are the same or different and are independently selected from the group consisting of H, C 1 -C 20 aliphatic, C 3 -C 20 cycloaliphatic, C 2 -C 20 heteroaliphatic, C 2 -C 20 heterocycloaliphatic, C 6 -C 20 aryl, C 2 -C 20 heteroaryl, and combinations thereof; and wherein: the C 1 -C 20 aliphatic, the C 3 -C 20 cycloaliphatic, the C 2 -C 20 heteroaliphatic, and the C 2 -C 20 heterocycloaliphatic is each optionally substituted one or more times with a moiety selected from the group consisting of CN, NO 2, OH, C 1 -C 5 alkoxy, C 1 -C 10 ester, C 1 -C 10 ketone, C 1 -C 10 ketimine, C 1 -C 10 sulfone, C 1 -C 10 sulfoxide, a C 1 -C 10 primary amide, and a C 1 -C 20 secondary amide; and an aryl ring of the C 6 -C 20 aryl and a heteroaryl ring of the C 2 -C 20 heteroaryl is each optionally substituted one or more times with a moiety selected from the group consisting of CN, NO 2, halogen, OH, C 1 -C 5 alkoxy, C 1 -C 10 ester, C 1 -C 10 ketone, C 1 -C 10 ketimine, C 1 -C 10 sulfone, C 1 -C 10 sulfoxide, a C 1 -C 10 primary amide, and a C 1 -C 20 secondary amide. Z is selected from the group consisting of C 1 -C 20 aliphatic, C 3 -C 20 cycloaliphatic, C 2 -C 20 heteroaliphatic, C 2 -C 20 heterocycloaliphatic, C 6 -C 20 aryl, C 2 -C 20 heteroaryl, and combinations thereof; X is selected from the group consisting of Cl, Br, and I; R 11, R 12, R 13 are the same or different and are independently selected from the group consisting of H, C 1 -C 20 aliphatic, C 3 -C 20 cycloaliphatic, C 2 -C 20 heteroaliphatic, C 2 -C 20 heterocycloaliphatic, C 6 -C 20 aryl, C 2 -C 20 heteroaryl, and combinations thereof; and wherein: the C 1 -C 20 aliphatic, the C 3 -C 20 cycloaliphatic, the C 2 -C 20 heteroaliphatic, and the C 2 -C 20 heterocycloaliphatic is each optionally substituted one or more times with a moiety selected from the group consisting of CN, NO 2, OH, C 1 -C 5 alkoxy, C 1 -C 10 ester, C 1 -C 10 ketone, C 1 -C 10 ketimine, C 1 -C 10 sulfone, C 1 -C 10 sulfoxide, a C 1 -C 10 primary amide, and a C 1 -C 20 secondary amide; and an aryl ring of the C 6 -C 20 aryl and a heteroaryl ring of the C 2 -C 20 heteroaryl is each optionally substituted one or more times with a moiety selected from the group consisting of CN, NO 2, halogen, OH, C 1 -C 5 alkoxy, C 1 -C 10 ester, C 1 -C 10 ketone, C 1 -C 10 ketimine, C 1 -C 10 sulfone, C 1 -C 10 sulfoxide, a C 1 -C 10 primary amide, and a C 1 -C 20 secondary amide. the C 1 -C 20 aliphatic, the C 3 -C 20 cycloaliphatic, the C 2 -C 20 heteroaliphatic, and the C 2 -C 20 heterocycloaliphatic is each optionally substituted one or more times with a moiety selected from the group consisting of CN, NO 2, OH, C 1 -C 5 alkoxy, C 1 -C 10 ester, C 1 -C 10 ketone, C 1 -C 10 ketimine, C 1 -C 10 sulfone, C 1 -C 10 sulfoxide, a C 1 -C 10 primary amide, and a C 1 -C 20 secondary amide; and an aryl ring of the C 6 -C 20 aryl and a heteroaryl ring of the C 2 -C 20 heteroaryl is each optionally substituted one or more times with a moiety selected from the group consisting of CN, NO 2, halogen, OH, C 1 -C 5 alkoxy, C 1 -C 10 ester, C 1 -C 10 ketone, C 1 -C 10 ketimine, C 1 -C 10 sulfone, C 1 -C 10 sulfoxide, a C 1 -C 10 primary amide, and a C 1 -C 20 secondary amide.