Synthesis of Ethyl cis-2--7-oxo-3-phenyl-6-phthalimido-1-azabicyclohept-3-ene-2-carboxylate and Methyl cis-2-Bromo-3-methyl-8-oxo-7-phthalimido-4-oxa-1-azabicyclooctane-2-carboxylate

Article abstract of DOI:10.1002/hlca.19890720711

Th synthesis of Δ¹-carbapenem and two β-lactams possessing a Br-atom at the N-substituting center not involved in the lactam ring and bearing the carboxyl group is described.The β-lactams having this kind of Br-substitution are more susceptible to nucleophilic attack than those having a conjugated double bond with the N-atom of the β-lactam ring.DBU is found to be an excellent reagent for the elimination of the silyloxy function.Moreover, a simple method for the addition of diethyl phosphite to an α,β-unsaturated double bond using a catalytic amount of NaH is described.