Straightforward Asymmetric Entry to Highly Functionalized Medium-Sized Rings Fused to β-Lactams via Chemo- and Stereocontrolled Divergent Radical Cyclization of Baylis−Hillman Adducts Derived from 4-Oxoazetidine-2-carbaldehydes
2-azetidinones fused to medium-sized rings via chemo- and stereocontrolled divergent radicalcyclization. The formation of bicyclic beta-lactams 4-6 could be rationalized through a tandem radicalMichaeladdition/endo cyclization or a tandem radicaladdition/Michaeladdition, depending on the electronic nature of the radical promoter.