Synthesis of fused or not β-lactam-biaryl hybrids by free radical aryl–aryl coupling of 2-azetidinone-tethered haloarenes

cis and trans-Aryl-2-azetidinone-tethered haloarenes can be stereoselectively prepared using the ketene–imine cyclization. These β-lactam-tethered haloarenes were used for the regiocontrolled preparation of β-lactam-biaryl hybrids including fused tetracyclic biaryl-2-azetidinones as well as C4-dearylated not fused biphenyl‐2-azetidinones via aryl–aryl radical cyclization and/or rearrangement. Alternatively, trans-dibenzocarbacephems could be stereoselectively prepared, both in racemic and enantiopure form, through the Staudinger reaction between phenanthridine and activated ketenes.