1-Carbapenam-2-one-3-carboxylic acid and 1-carba-3-hydroxy-3-cephem-4-carboxylic acid and esters thereof are provided by a process comprising a rhodium C.sub.2 -C.sub.10 carboxylate catalyzed cyclization of an ester of a 4-(1-alkoxy- or 1-substituted alkxoy)-2-oxo-4-azetidinyl)-.alpha.-diazo-.beta.-ketobutyric acid and an ester of a 5-(1-alkoxy- or 1-substituted alkoxy-2-oxo-4-azetidinyl)-.alpha.-diazo-.beta.-ketovaleric acid respectively. The process is carried out in an inert organic solvent at a temperature between about 15.degree. C. and about 85.degree.0 C. The 1-carba bicyclic .beta.-lactams are intermediates for preparing antibiotics.
1-羧基-2-羧基-3-羧基-4-羧基-1-羧基-3-羢基-3-头孢-4-
羧酸及其酯是通过以下过程提供的:在惰性有机溶剂中,通过
铑C.sub.2-C.sub.10
羧酸酯催化的环化反应,将4-(1-烷氧基或1-取代烷氧基)-2-氧代-4-氮杂环丙基)-α-重氮-β-酮
丁酸酯和5-(1-烷氧基或1-取代烷氧基-2-氧代-4-氮杂环丙基)-α-重氮-β-酮
戊酸酯分别进行环化。该过程在约15°C至约85°C的温度下进行。1-羧基双环β-内酰胺是制备抗生素的中间体。