A short and stereoselective synthesis of the carbapenem antibiotic PS-5

Abstract
The benzyl ester (3) and p-nitrobenzyl ester (PNB ester)(4) of the antibiotic PS-5 and the bis-protected PS-6 (5) were stereoselectively synthesised by application of the new carbon–carbon bond formation reaction at the C-4-position of 4-acetoxy-3-ethyl- or 4-acetoxy-3-ethyl- or 4-acetoxy-3-isopropyl-azetidin-2-ones [(10) or (11)].