3.beta.-succinimidoazetidinones as chiral intermediates

The compound of the formula ##STR18## wherein R and R.sub.1 are C.sub.1-C.sub.5 alkanoyloxy, benzoyloxy, a mono- or di-substituted benzoyloxy group substituted by C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 alkoxy, halogen, cyano, nitro, amino, or C.sub.1 -C.sub.4 alkoxy carbonyl, benzyloxy, diphenylmethoxy, or triphenylmethoxy;

• or one of R and R.sub.1 is hydrogen and the other is C.sub.1 -C.sub.5 alkanoyloxy, benzoyloxy, a substituted benzoyloxy group as defined above, benzyloxy, diphenylmethoxy or triphenylmethoxy;
• R.sub.2 is C.sub.1 -C.sub.4 alkoxycarbonyl or a grop represented by the formula ##STR19## wherein R.sub.4 and R'.sub.4 independently are hydrogen or C.sub.1 -C.sub.4 alkyl, R.sub.5 is phenyl, naphthyl, m-(C.sub.1 -C.sub.4 alkoxy) phenyl, furyl, or protected carboxy;
• and
• R.sub.3 is protected-carboxymethyl, an NH protecting group or a 1-(protected carboxy)-2-propanone ketal or thioketal group represented by the formula ##STR20## wherein R.sub.6 is a carboxy-protecting group, y and y' are both oxygen or sulfur, and R.sub.7 and R.sub.7 ' when taken separately are C.sub.1 -C.sub.4 alkyl, and when taken together are --CH.sub.2 --CH.sub.2 -- or --CH.sub.2 --CH.sub.2 --CH.sub.2 -- which with the oxygen or sulfur atoms to which they are bonded form a 5- or 6-membered ring.