Approaches are described towards synthesis of 1-hydroxy-1-carba-cephalosporin (1), a chemically interesting nuclearly modified cephalosporin analogue which may possess potent antibiotic activity. Approaches to a bicyclic tetrahydropyridine (27), potentially convertible into carbacephem (1), are also discussed. Oxygenated 1-carbacephems (95) and (97) have been prepared via a route employing the reaction between imines and a ketene precursor to give beta-lactams. The 1alpha-isomer (95) exhibited weak antibiotic properties
