The present invention relates to compounds of formula (I) and a process for producing the same. In formula (I), X represents a halogen atom, and R.sup.1 represents group --COR.sup.2 wherein R.sup.2 represents group OM or C1-12 alkyloxy wherein M represents a hydrogen atom, an alkali metal, an alkaline earth metal, or quaternary ammonium. The use of this compound as a synthetic intermediate can realize the production of carbapenem derivatives having potent antimicrobial activity in an efficient and safe manner at low cost. ##STR00001##