A novel access to 3-hydroxycephems was attained from penicillin G via the C=C bond cleavage of 1-(1-alkoxycarbonyl-2-chloromethyl-2-propenyl)-4-(phenylsulfonylthio)-2-azetidinones by successive treatment with RuCl3/HIO4 and HIO4/CuSO4 and reductive cyclization of 1-(1-alkoxycarbonyl-3-chloro-2-hydroxy-1-propenyl)-4-(phenylsulfonylthio)-2-azetidinones on treatment with a newly devised BiCl3/Sn or TiCl4/Sn bimetal redox couple in DMF containing pyridine.
                                    通过 RuCl3/
HIO4 和     /CuSO4 相继处理 1-(1-烷氧羰基-3-
氯-2-羟基-
1-丙烯基)-4-(苯磺酰
硫基)-
2-氮杂环丁酮,以及 1-(1-烷氧羰基-3-
氯-2-羟基-
1-丙烯基)-4-(苯磺酰
硫基)-
2-氮杂环丁酮的还原环化,从
青霉素 G 中获得了一种新的 
3-羟基头孢菌素。1-(1-烷氧基羰基-3-
氯-2-羟基-
1-丙烯基)-4-(苯磺酰
硫基)-
2-氮杂环丁酮在含
吡啶的 
DMF 中用新设计的 
BiCl3/Sn 或 TiCl4/Sn 双
金属氧化还原对偶进行处理。