Abstract Short syntheses of Ritipenem Acoxyl 1a and Ritipenen 1b are reported. The syntheses start from (R)-4-acetoxy-(S)-3 [(R)-1-(t-butyldimethylsilyloxy) ethyl] azetidin-2-one 3 and are based on the incorporation of two 2C units obtained by manipulation of glicolyc acid 4.
