The Beta-lactams antibiotics are perhaps the most widely used and studied antibiotics. The preparation of totally synthetic and semisynthetic antibiotics is vital to a development of an understanding of the structural-function relationship of the Beta-lactam antibiotics and the mode of action of the Beta-lactamase enzymes of bacterial origin. While one of the most efficient and useful methods of preparation of the Beta-lactam unit has been the cyclization of Beta-haloamides, the strongly basic conditions required are often incompatible with the peripheral substitution appropriate for structural elaboration. The generation of nitrogen anions from substituted hydroxamic acids and subsequent cyclization will allow the preparation of Beta-lactam derivatives under conditions milder (pH approximately 7) than hitherto demonstrated. In addition to its biosynthetic analogy, the procedure will allow direct elaboration to a variety of structurally modified Beta-lactams of biological importance including the newly discovered novel nocardicin antibiotics, Beta-lactamase inhibitors (clavulanic acid analogs) and even the penicillins and cephalosporins. The intermediate hydroxamic acids also demonstrate unique chemical and perhaps biological properties which have yet to be exploited.