The present invention provides β-methyl carbapenem compounds and pharmaceutical compositions useful in the treatment of bacterial infections and methods for treating such infections using such compounds and/or compositions. The invention includes administering an effective amount of a carbapenem compound or salt and/or prodrug thereof to a host in need of such a treatment. The present invention is also in the field of synthetic organic chemistry and is specifically provides an improved method of synthesis of β-methyl carbapenems which are useful as antibacterial agents.