Download full text in PDF Opens in a new window. Article suggestions will be shown in a dialog on return to ScienceDirect. ... Please enable JavaScript to use all the features on this page. ... Optically pure 4-acetoxy-3-[1-(t-butyldimethylsilyloxy)ethyl]-2- azetidinone( ), which is a highly versatile intermediate for the synthesis of thienamycin( ) and other biologically active [β-lactam analogs, was synthesized from 4-carboxy-3-[1-(t-butyldimethylsilyloxy)ethyl]-2-azetidinone ...