Synthesis of 3-aminoalkyl substituted carbapenems via a phosphorane intermediate

Reaction of azetidinone phosphoranes $\text{1}$ with aldehyde $\text{8}$ gave the olefins $\text{4}$, which were converted into carbapenem esters 6 in 4 steps. Hydrogenation of $\text{6}$ gave the title compounds.